Over the years, our writers have been present for some of the game's greatest occasions. In the final installment of a multipart series, they tell the story of the best team they have seen in person, which include Pep Guardiola's Barcelona, Sir Alex Ferguson's Manchester United and the Spain side that won three major trophies from 2008 to 2012.

Sid Lowe's pick: Barcelona, 2008-12

Highlights: Won Champions League (twice), La Liga (three times), Copa del Rey (twice) and Club World Cup

Take the ball, pass the ball; take the ball, pass the trophy ... one after another, after another.

In the four years that Pep Guardiola was coach of FC Barcelona, the club won 14 of 18 competitions, among them the European Cup in 2009 and 2011, as well as three consecutive Liga titles.

There was also the World Cup, which though won by Spain, felt a little like it belonged to Barcelona -- or so some liked to say. Joan Laporta, club president at the time, once said that the national team was just wearing the wrong shirts.

No, Laporta should not be taken too seriously, but it is true that six of the starters -- Carles Puyol, Gerard Pique, Sergio Busquets, Xavi, Andres Iniesta and Pedro -- when La Roja beat Netherlands in 2010 were Barcelona players, and a seventh, David Villa, was about to be.

All of which helps underline that it was not really what Barcelona won; it was the way they won and with whom they won. It was that the Ballon d'Or podium was filled with graduates of the club's La Masia academy, led by Lionel Messi, who won the award every year in this period. It was the fact that even when they were fortunate -- like the 2009 night they edged past Chelsea and into the Champions League final -- it never really felt like luck, just logic.

You could find them more or less exciting and enjoy other teams more, but there was no argument: Barcelona were just better than everyone else, an epoch-defining team that changed the paradigm, playing differently to the rest. So good, so dominant -- not once during this period did they have less than 50% possession of the ball in a game -- that they forced Real Madrid to declare footballing war and obliged every team there was to change to cope with them. Most still could not, for all the parked buses and best-laid plans.

That Barcelona team won 14 of 18 possible titles, and here's the thing: It probably should have been more. They lost a Copa del Rey final against Real Madrid to a Cristiano Ronaldo goal in extra time.

They lost two Champions League semifinals, the first of which was due in part to an Icelandic volcano that affected their travel plans. (And forget Jose Mourinho's mythology in that tie; Barca were robbed against Inter in 2010.)

In the second, two years later, Chelsea won without really knowing how. At Stamford Bridge, one player from the home side left laughing, unable to believe that they had not been beaten -- Chelsea won 1-0 -- and admitting Barcelona had been infinitely superior ... just like they were week after week, game after game.

Mostly there could be no escaping the truth: This team was something else. Sir Alex Ferguson talked about how Barcelona got you "on that carousel" and there was no way off. The 2011 Champions League final showed that: a beating no one else had given United, according to their manager.

The first Clasico against Mourinho showed it too; Barcelona beat Madrid 5-0, taking them to pieces so smoothly, so completely. The result was no one-off; it meant five straight league wins under Guardiola against the big rivals, with an aggregate score of 17-2. Madrid had been helpless, like everyone else.

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Tom Marshall's pick: Manchester United under Sir Alex Ferguson, 1986-2013

Highlights: Won Champions League (twice), Premier League (13 times), FA Cup (five times), League Cup (four times), Club World Cup and Cup Winners' Cup

The sheer consistency and ability to respond to different challenges over 26 years was remarkable, as Ferguson crafted exceptional teams that won Champions League titles in 1999 and 2008, but also claimed silverware with squads that were not necessarily outstanding. Other managers have overseen sides that broke the mold in terms of tactics and playing philosophy, but Ferguson's were the best at adapting quickly.

United won 38 trophies during Ferguson's time at Old Trafford -- 13 of the first 21 Premier League crowns went their way and they lost three others on the last day of the season in question -- and were the gold standard. It might be a long time before another manager and club combine for such sustained success, while the relative struggles of the club since he retired is a further sign of his impact.

Graham Hunter's pick: Spain, 2008-12

Highlights: Won World Cup and European Championship (twice)

For my taste, the only real competition for Barcelona from 2005 to 2015 is Spain's three-tournament winners. What separates them? The brand of football played by Pep Guardiola's Barcelona in 2009 and 2011 is, if not unequalled, the best in living memory.

But international football does not have a transfer market, and tournaments come at the end of long, draining seasons, so for that reason I have to go with Spain. The breakthrough came at Euro 2008 under Luis Aragones, before Vicente Del Bosque oversaw success at the 2010 World Cup and Euro 2012.

Nicky Bandini's pick: Inter, 2009-10

Highlights: Won Champions League, Serie A and Coppa Italia

There are extraordinary teams I saw only once, while others feel more significant because I watched them more often. Jose Mourinho's treble-winning side belong to the latter category, and they only won Serie A on the final day of the season. Yet there was a unity of purpose -- embodied by Samuel Eto'o playing full-back against Barcelona in a Champion League semifinal -- that made their eventual triumphs feel inevitable.

Beyond that innate, manager-instilled ability to do whatever it took to win, between Eto'o, Wesley Sneijder and Diego Milito, Inter also had special individual talent. It ended almost as quick as it began, when Mourinho bolted for Real Madrid straight after beating Bayern Munich in the Champions League final, but that season belonged to the Nerazzurri.

Julien Laurens' pick: Arsenal, 2003-04

Highlights: Won Premier League without being beaten

The "Invincibles" went unbeaten in the league not just thanks to incredible talent and physical abilities, but also because of mental strength and confidence. They rotated their squad for an FA Cup semifinal against Manchester United and lost 1-0 only after hitting the woodwork twice, while they also were unfortunate to exit the Champions League in the quarterfinals, despite being the better side in both legs against Chelsea.

Led by Thierry Henry, who scored 30 league goals in 37 games, as well as Patrick Vieira, Robert Pires, David Bergkamp and Sol Campbell, Arsene Wenger's Gunners were one of the truly great sides, despite only collecting one trophy.

Jeff Carlisle's pick: Spain, 2010

Highlights: Won World Cup

Spain did not blow away the opposition at the World Cup in South Africa -- they lost their first game to Switzerland and won every knockout-round game 1-0 -- but this was a tournament in which just about every team tried to stifle their tiki-taka ways. Yet La Roja managed to get the job done, claiming the second of what turned out to be three straight trophies.

Six Spain players -- Iker Casillas, Sergio Ramos, Carles Puyol, Xavi, Andres Iniesta and David Villa -- made the team of the tournament in South Africa and, along with Gerard Pique, Sergio Busquets, Xabi Alonso and Fernando Torres, formed what became what can only be described as a footballing dynasty.

Mark Ogden's pick: Juventus, late 1990s

Highlights: Won Champions League, Serie A (three times) and Coppa Italia

Marcello Lippi built a formidable team that was a dominant force, even if they only one won of the three successive Champions League finals they reached; that triumph, in 1996, came on penalties against holders Ajax. A squad boasting the likes of Zinedine Zidane, Alessandro Del Piero, Antonio Conte and Edgar Davids has become something of a forgotten superteam, but it would be a match for any of the great club sides to emerge since.

Gab Marcotti's pick: Barcelona, 2008-12

Highlights: Won Champions League (twice), La Liga (three times), Copa del Rey (twice) and Club World Cup

If I were older, I might have said Arrigo Sacchi's Milan. But Pep Guardiola's Barcelona team not only won two Champions League crowns and three Liga titles, they also redefined the way the game is played, bringing back possession football and pressing. Moreover, they did so in the last two seasons of this run against Jose Mourinho in his pomp with a Real Madrid squad that was the most expensively assembled in history.

Nick Miller's pick: Manchester United, 1996-2001

Highlights: Won Champions League, Premier League (five times), FA Cup (twice)

The peak years of Sir Alex Ferguson's second great United team were astonishingly good. With Roy Keane surrounded by an absurd collection of youth team products, they combined superb football with a merciless drive to win that was ruthless and beautiful. No team will win a treble like they did in 1999, claiming the Premier League by a single point over Arsenal on the final day of the season, the FA Cup after a stunning Ryan Giggs goal against Arsenal in the semifinals and the Champions League final courtesy of two goals in second-half injury time.

Tor-Kristian Karlsen's pick: Milan, mid-1990s

Highlights: Won Champions League, Serie A (four times)

Fabio Capello's team got me hooked on the tactical side of football. From my perspective, that Rossoneri team appeared to be almost unbeatable and a perfect case study in discipline and leadership. They won Serie A in four of five seasons, while the arguable microcosm of their qualities was shown in the 1994 Champions League final, when they thrashed Barcelona's "Dream Team" -- including Romario, Pep Guardiola, Ronald Koeman, Hristo Stoichkov -- by a score of 4-0.

Tom Williams' pick: Manchester City, 2017-19

Highlights: Won Premier League (twice), FA Cup and League Cup (twice)

I never saw Pep Guardiola's Barcelona live, but his Man City side in this period thrilled me on the most consistent basis. They are one of the few teams I can think of that had their own trademark goal -- pass inside the full-back, low cross, back-post tap-in -- and at their best were an absolute joy to behold. They never quite managed to win the Champions League, but they did break the 100-point barrier in Premier League play and, during this period, won five of the six trophies on offer in England.

Rob Dawson's pick: Barcelona, 2008-12

Highlights: Won Champions League (twice), La Liga (three times), Copa del Rey (twice) and Club World Cup

As part of winning six trophies overall in 2009, Pep Guardiola's side destroyed a very good Manchester United team in Rome to win the European Cup and were absolutely incredible to watch. Two years later, it was a similar story at Wembley; the score in the Champions League final was 1-1 at half-time, but United fans were subdued, almost as if they knew what was coming in the second period. They were correct.

Colin Udoh's pick: Argentina, 2008 Olympics

Highlights: Won Olympic gold

The team that won the 2008 Olympic gold medal, beating Nigeria in the final after seeing off Brazil in the semis, was packed with talent and full of confidence and played with a sense of freedom and a happy-go-lucky spirit. Led by Lionel Messi, Angel Di Maria and Sergio Aguero -- all Under-23s at the time -- as well as overage midfielders Javier Mascherano and Juan Roman Riquelme, Argentina ran through the tournament unbeaten, winning their six games by a total score of 11-2.