Chelsea 2 Sheffield United 0
There was an hour on the clock when Thomas Tuchel erupted at his players. This was supposed to be a stroll against the Premier League's bottom side, but it was threatening to turn into an awkward afternoon.
Sheffield United were fighting for their interim manager, Paul Heckingbottom, and Chelsea's route into the last four of the FA Cup was starting to look uncertain.
Ever the perfectionist, Tuchel struggled to hold in his frustration.
Chelsea’s manager could smell complacency. He could see the warning signs; he knew an equaliser was on the cards. This quarter-final had finally come alive and it was United who were calling the shots, bossing midfield and repeatedly breaking beyond Chelsea on the left. Something had to change.
There was no hesitation from Tuchel, who had an unbeaten record to protect.
He bellowed at his lethargic side and made changes after 63 minutes, hooking Andreas Christensen and the disappointing Olivier Giroud and sending on César Azpilicueta and Reece James with instructions to lock down Chelsea's faltering right side. It was a defensive change and a mark of respect to United, who had taken control after barely competing in the first half.
The mood had changed. At the outset this simply felt like a demonstration of Chelsea's strength in depth. Tuchel made nine changes after reaching the last eight of the Champions League at the expense of Atlético Madrid and although Heckingbttom must have been pleased to see Timo Werner, Hakim Ziyech and Kai Havertz on the bench, it would be pushing it to call it a weakened Chelsea side when they could bring in Italy's Emerson Palmieri as a left-sided centre-back and give Giroud, a world champion forward, his first minutes since February 28th.
Yet Chelsea, who were without Tammy Abraham because of a persistent ankle problem, began to fret as the game wore on. Their lead, carved out when Oliver Norwood turned a Ben Chilwell shot into his own net midway through the first half, was under threat. United pushed even after Tuchel's changes. Oliver McBurnie threatened with a firm drive, Irish left back Enda Stevens headed wide from close range and it took a fine save from Kepa Arrizabalaga, making a rare start in goal for Chelsea, to deny the tireless David McGoldrick what would have been a deserved equaliser.
Heckingbottom's side, who are surely destined to return to the Championship despite parting company with Chris Wilder last week, gave everything for the United badge. They even forced Tuchel to bring on Ziyech and Havertz. Billy Gilmour, the 19-year-old midfielder, had tired in Chelsea's midfield after a bright first half.
In the end, though, Chelsea had too much quality in attack. United were not ruthless enough when changes arrived. Chelsea, yet to taste defeat in Tuchel's first 15 games, showed them how to finish when Ziyech wrapped up victory in added time, volleying past Aaron Ramsdale from close range.
Rhian Brewster had almost equalised moments earlier, only to fire wide from an inviting position.
Brewster’s miss summed up United’s season. Once again they lacked a cutting edge and fell to more decisive opponents. After a tight start Chelsea increased the tempo midway through the half, opening United up on the right flank. Callum Hudson-Odoi, pushing forward from wing-back, fizzed a low cross towards the near post. Giroud attacked the ball and forced Ramsdale to concede a corner.
The danger had not passed. Mount swung the corner deep to the far post and although nobody could connect in the middle, United were slow to react when Chilwell collected possession on the edge of the area. The left wing-back had time to set himself before unleashing a low drive and although his shot was heading wide, Norwood’s touch took the ball past Ramsdale.
Chelsea had chances to double their lead, Ramsdale denying Christian Pulisic on two occasions. Yet United resisted. They began to play at long last and their big moment arrived when a loose ball fell to Brewster, who fired wide. Ziyech would soon show the young forward how to finish. - Guardian