Andy Murray admitted "it wasn't a great day" after his Wimbledon title defence came to a crashing halt at the hands of Grigor Dimitrov.
In a surprisingly flat performance, Murray folded in straight sets against the Bulgarian, losing 6-1 7-6 (7/4) 6-2 on Centre Court in the quarter-finals.
Murray said on BBC One: "I'm disappointed, especially disappointed with the way I started the match.
"I played a poor first set and that gave him confidence at the beginning.
"In the second set he got tight at the end and it could have gone either way. When he got that set it's a lot easier to settle down when you're two sets to love up.
"If I had managed to come back with him having been a break up in that set and got it, maybe I would have been able to find a way back, but it wasn't a great day."
Dimitrov suggested Murray had been off his game from the warm-up onwards, but Murray disagreed.
"I felt fine in the warm-up," he said. "I obviously got off to a bad start so that was the disappointing part of the match for me.
"I found a way to get myself back into it at the end of the second set but the start was not good enough. You need to start better."
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Discussing Dimitrov's display, Murray said: "It's hard to analyse everything that happened but he played a very solid match. He made very few mistakes, he served well and made a lot of returns.
"All the percentages were in his favour today and he played a very good match. I just wish I played a bit better and made it a bit tougher for him at times."
Dimitrov will now prepare for his first grand slam semi-final.
"I'm excited. I'm just happy to get through that match in straight sets," said the 23-year-old.
"It's never easy coming to play against Andy, especially in front of a home crowd. I've been pretty fortunate today and I'm just happy."