Tammy Abraham is Chelsea's hero at both ends against FA Cup underdogs Barnsley

Chelsea's Tammy Abraham (right) celebrates with team-mate Reece James. PA

Chelsea reached the FA Cup quarter-finals with a hard-fought 1-0 win at Championship side Barnsley on Thursday settled by a goal from centre forward Tammy Abraham as the Blues notched up their fourth win in five games under new manager Thomas Tuchel.

Abraham also denied Barnsley a late equaliser when he stretched to get a head to substitute Michael Sollbauer's goal-bound flick.

The Londoners started with 10 changes from their last Premier League match and struggled to find any rhythm in the first half as Barnsley, mid-table in England's second tier, refused to be cowed by their big-name opponents.

The hosts created the better chances and Tuchel responded at halftime by switching to four in defence, bringing on full back Reece James to replace Marcos Alonso and centre half Antonio Rudiger for Andreas Christensen who had suffered a head injury.

The decisions paid off in the 64th minute when James, fed by 19-year-old Billy Gilmour, raced into space and his cross set up Abraham for an easy finish.

"I knew that chance was going to come eventually and I just had to be in the right place at the right time," Abraham told the BBC.

He said his goalline clearance harked back to his childhood days as a defender.

"I saw the ball come in and I said 'I have to do this, I have to try something', and it worked."

Barnsley were left to rue missed chances in the first half when Callum Brittain shot straight at Chelsea goalkeeper Kepa Arrizabalaga from close range and another Brittain shot was deflected just wide.

As well as Tuchel's fourth victory since he replaced Frank Lampard last month, it was the fourth clean sheet for the Blues under the German who praised the players who stepped into the side.

"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," Tuchel said. "We can do better but I don't want to be too hard on the players."

Chelsea, who lost last year's FA Cup final to Arsenal, will host Sheffield United in the sixth round, having beaten the Yorkshire side twice in the league this season, including last week's 2-1 away win.