BARNSLEY, England -- As Christian Pulisic left the pitch at Oakwell, substituted in the 80th minute of Chelsea's 1-0 FA Cup fifth-round win at Barnsley, the United States captain bore the expression of a man who had just left an audition with the feeling that he had forgotten his lines.

The 22-year-old had at least contributed to an important victory, helping Thomas Tuchel's team secure a quarterfinal tie at home to Sheffield United next month following Tammy Abraham's 64th-minute goal -- a strike that appeared potentially offside, but could not be checked by VAR because the English Football Association strangely chooses to only operate the system at Premier League grounds. Yet although Pulisic played his part, he was as unconvincing as Chelsea were collectively. Indeed, the only time he looked happy was at the end of the cup tie, when he shared a brief catch-up on the pitch with Barnsley forward and U.S. teammate Daryl Dike before jogging to the visitors' dressing room.

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Having emerged as a key player for former manager Frank Lampard in the second half of last season, Pulisic's second season in English football has been a struggle for the former Borussia Dortmund star, and this forgettable night at Barnsley summed up his difficult campaign. He wasn't the only one to disappoint, however, and Tuchel was clear in his assessment of Chelsea's performance.

"Not enough courage and it was too deep for a long, long time," he said after the match. "We clearly can play better, so yes I expected more, but not in terms that I am frustrated.

"If you lack a rhythm and a bit of self-confidence and you have to show on this pitch, against an opponent that takes all the risk and plays the game of his life, that is not easy. We can do better, but I don't want to be too hard on the players."

Injuries have denied Pulisic a clear run of games, and his form has been hit as a result. He has scored just twice all season in all competitions and hasn't hit the back of the net in 13 appearances since the 3-1 win against Leeds United in December.

But on a night when Tuchel, who replaced the sacked Lampard last month, made 10 changes to his starting lineup, Pulisic was handed the chance to kick-start his season. This was his first start under Tuchel, having made substitute appearances prior to this game, and the opportunity was clear: make an impact and increase his chances of starting against Newcastle United in the Premier League at the weekend.

But on a heavy pitch, it didn't happen for Pulisic. In the first half, he was deployed on the left of an attacking three before being switched to the right after the interval.

Through no fault of his own, Pulisic spent the entirety of the game on the side of the pitch that had large, grassless areas of mud, making it harder to control the ball and play simple passes. Perhaps that was why the ball evaded him so often, with Chelsea opting instead to play through the middle or on the other side of the pitch in order to keep control, but regardless of the playing surface, Pulisic needed to do more.

There were two flashes of inspiration from the American: a link-up with Billy Gilmour that resulted in a stray pass to Abraham, and a run through the centre that ended with a tame effort at goal after Pulisic played a one-two with Callum Hudson-Odoi. The second half was even less eventful for him as Chelsea toiled away, but by the time he was replaced by Mateo Kovacic, Pulisic could have given Tuchel much more to consider when he selects his next team.

Tuchel, of course, knows Pulisic well, having worked with the then-teenager at Dortmund. The new Chelsea manager knows what his charge has to offer and is fully aware of Pulisic's strengths and weaknesses. So he will be given opportunities to stake a claim for a starting spot, but the competition is fierce at Stamford Bridge.

It was tough enough last season, when Lampard favoured Mason Mount in the early stage of the campaign, but the summer arrivals of Timo Werner, Hakim Ziyech and Kai Havertz have only intensified the battle for places up front. Werner and Havertz were given the night off at Barnsley, but the German duo also have plenty to do to prove they deserve a starting spot of their own. Unlike those two, Pulisic has at least proved himself in the Premier League.

But this was an opportunity missed to remind his manager and teammates of his capabilities. Against a mid-table Championship team, Pulisic could have grabbed the headlines and inspired Chelsea.

In the end, nobody in a Chelsea shirt truly stood up and led from the front. They got the job done, and avoided a repeat of their 2008 FA Cup humiliation here at Oakwell, but it was anything but impressive. And that should disappoint Pulisic on a night when he could have made a big statement.