Thomas Tuchel felt his Chelsea side showed a lack of courage and said he "expected more" from them in a 1-0 FA Cup fifth round victory at Barnsley.

Tammy Abraham's 12th goal of the season after 64 minutes at Oakwell on Thursday ensured the Blues will face Sheffield United in the quarter-finals at Stamford Bridge on the weekend of March 20-21.

That was the London club's only short on target as well-drilled Championship side Barnsley put up a great fight after being hammered 6-0 by the same opponents in the EFL Cup last September.

Tuchel switched to a back four at half-time, replacing Andreas Christensen - who took a knock on the head - and Marcos Alonso with Antonio Rudiger and Reece James.

The Chelsea head coach has overseen four wins and a draw since replacing Frank Lampard last month, conceding just one goal in the process, but wanted to see more from a much-changed side.

Tuchel, who cut an animated figure on the touchline, said: "The changes [he made at half-time] made it a little easier to get into the opponent's half and overcome the first press.

"We did it well at the start of the second half and played constantly in the opponents half. We scored the goal and I had the feeling that they increased the risk but we stepped down in the little decisions.

"Not enough courage and it was too deep for a long, long time. 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."

Chelsea beat the Blades 2-1 at Bramall Lane last weekend but Tuchel is happy not to be travelling back to South Yorkshire to face a team who are bottom of the Premier League and looking destined for the drop.

On playing Sheffield United in the last eight: "It’s going to be a tough one. They are a very physical team that presses high. They are organised but I am happy to have a home game. This is what we wanted."