Eight of this season's Heineken Champions Cup last-16 teams have been confirmed - but half of the places are still up for grabs.

So what are the key talking points from round three and the penultimate weekend of the pool stage?

BBC Sport takes a look at five things we learned.

Daly and Smith boost Six Nations chances

Europe's premier club competition has taken centre stage since the turn of the year, but many of the players involved will have one eye on selection for the forthcoming Six Nations.

Elliot Daly was not picked in England's squad for the Autumn internationals - the last chosen by Eddie Jones - and he would have wanted to produce a sparkling display in front of new England coach Steve Borthwick in Saracens' game with Lyon.

It did not take long for the experienced full-back to make his mark as Borthwick watched at the StoneX Stadium.

Daly scored a seven-minute hat-trick with three excellent finishes in the 48-28 win to put himself firmly in the frame for an England recall.

Harlequins' Marcus Smith has not played since England's defeat by South Africa in November and any match rust would be under the spotlight when the fly-half came up against influential Scotland foe Finn Russell as his opposite number in the game at Racing 92.

Smith started slowly as Russell orchestrated his backline and Racing took control, but the 23-year-old sparked into life after the break and had a hand in both of Cadan Murley's tries.

Quins may have narrowly lost 30-29 but Smith's ability to stand up defenders and glide past them, as well as his accurate kicking, caught the eye.

Referees lay down a marker

There were five red cards handed out during round three as players were penalised for high tackles and direct head contact.

Sale's Cobus Wiese, Exeter's Henry Slade, Munster's Jack O'Donoghue and London Irish pair Ben Loader and Ciaran Parker were all sent off at the weekend.

Referees moved to protect players by brandishing red cards for direct head contacts, while some may feel mitigating circumstance were not always taken into account.

One of those was London Irish boss Declan Kidney, who said he was concerned by the impact of "trial by TV".

He added: "TV is a massive part of the game and we need to work together, but I think there is a bit of trial by TV.

"It's such an emotive and talked-about process at the moment, for the process to get a fair hearing it is wrong to try and score points.

"The [disciplinary] system will go through what it is and what you want then is a fair hearing at the end of it.

"TV is a hugely important aspect of the whole sport, but it's the balancing act of having the decisions made before the process takes place during the week."

Kidney explained: "There was a time before the TMO, or anything came into it, that you had to make instinctive decisions over foul play and what was a collision.

"Is the game safer now as a result? It probably is. But on one hand we are asking TMOs not to intercede and speed the game up, but on the other, once you break something down second by second then the way it looks can be substantially different.

"Things are happening which aren't being reviewed and then others are microscopic and get a huge amount of air time. Is it right that happens?

"One could argue yes, but one could also argue that if everything is microscopically looked at, we'd be here all day."

Scottish representation secured

Scottish side Edinburgh are through to the last 16 after a comfortable 34-21 win at Castres,

Despite Dave Cherry and Bill Mata's first-half tries, the French side led after Josaia Raisuqe, Adrien Seguret and Wilfrid Hounkpatin all crossed.

But Mike Blair's side were much improved after the break and Cammy Hutchison and Ben Vellacott got over the whitewash to ensure a bonus point.

Meanwhile, Ospreys are flying the Welsh flag in Pool B but are yet to seal qualification, even after a 35-29 win over French champions Montpellier.

Alex Cuthbert scored twice, Justin Tipuric and Morgan Morris also crossed, with Cai Evans kicking 15 points. Ospreys can qualify with a point from their next round game against Leicester, who have already qualified with three wins from three.

A South African clean sweep...almost

Three South African teams entered the tournament for the first time this season and, with Sharks already into the knockouts, Bulls and Stormers are not far behind.

Sharks cruised past Bordeaux Begles 32-3 to book their place in the last 16, while both Bulls and Stormers need just a point each to seal qualification.

Bulls avenged last month's defeat at Exeter Chiefs with a bonus-point 39-28 victory over the Premiership side's 14 men, while Stormers had too much for the 13 men of London Irish with a 28-14 away win.

Can anyone stop Leinster?

Four-time champions Leinster top Pool A with the full complement of 15 points after three wins from their opening three games.

The Irish province have amassed 148 points and scored 22 tries - eight more than anyone else in the competition.

Leinster booked their last-16 spot by hammering Gloucester 49-14 at Kingsholm as Jordan Larmour, Michael Ala'alatoa, Jamie Osborne and Caelan Doris tries secured a first-half bonus point.

Ireland internationals Hugo Keenan, Josh van der Flier and Ronan Kelleher added further tries in the second half.

It's looking ominous for the rest...