Chelsea beat Sheffield United 2-0 on Sunday thanks to an own goal by Oliver Norwood and winger Hakim Ziyech's late strike to reach the FA Cup semi-finals for the fourth time in five seasons.
The victory at Stamford Bridge extended Chelsea manager Thomas Tuchel's unbeaten start in London with the German winning 10 matches and drawing four in all competitions since replacing Frank Lampard in January.
Chelsea have moved into contention for a top-four finish in the Premier League and reached the Champions League quarter-finals but Tuchel said he witnessed a tired performance from his team.
"It sounds excellent to say we're through to the semis - it was a tough match. We had a good first half where we controlled everything," Tuchel told the BBC.
"We lost control in the second half, we were clearly tired. After 14 consecutive matches I could feel we were tired and we made many little faults.
"We were lucky to keep the clean sheet in the second half... It's important to go through in the Cup. That was the target and we reached it."
Sheffield United, bottom of the Premier League, showed early attacking intent but fell behind in the 24th minute when Norwood steered the ball into his own net as he attempted to block Ben Chilwell's shot.
With the Blades throwing men forward in the dying seconds, Ziyech produced a fine finish after a quick counter-attack to seal Chelsea's win in added time.
Chelsea could have scored another through Christian Pulisic, but the American forward lost his footing and his shot was blocked by Aaron Ramsdale.
"We have a confident bunch of guys here and when you go on a streak like this we're feeling really good and we're feeling like we can beat anyone," Pulisic said.
Sheffield United were rejuvenated after the break but lacked the killer instinct in front of goal and squandered a couple of clear chances.
Tuchel's side will discover who they face in the last four when the draw is made at halftime of the quarter-final between Leicester City and Manchester United later on Sunday. The semi-finals take place next month with the final on May 15.
(Reporting by Shrivathsa Sridhar in Bengaluru, editing by Ed Osmond)
