Murray, who had not dropped a set coming into the contest, never looked to be in the match except for portions of the second set.
''I started the tournament well. I was playing good tennis. Today was a bad day, you know, from my side. I made many mistakes, unforced errors, and then started going for too much and taking chances that weren't really there,'' said Murray.
Murray was also reported to have screamed on court about something that happened ''five minutes'' before his match began, but did not explain what he had been referring to.
The 2013 Wimbledon champion has lost in straight sets at all three Grand Slams played this year, and was critical of his performances at the majors.
''I need to go away and make a lot of improvements in my game. I've lost a couple of matches in the last few Slams where I've lost in straight sets and, you know, played poorly,'' said Murray, who returned from back surgery at the beginning of the season.
''So I need to have a think about things, what are the things I need to improve, and get myself in better shape and work even harder. Because everyone's starting to get better. The younger guys are now obviously becoming more mature and improving all the time. I need to make some improvements to my game.''
With 22-year-olds Milos Raonic and Dimitrov both reaching the Wimbledon semifinals and entering the Top 10, as well as 19-year-old Nick Kyrgios upsetting Rafael Nadal to reach the quarterfinals, Murray says there is now more pressure on the top players to perform if they want to keep up their results.
''I don't feel like I have improved so much since Wimbledon last year, I think I've played some very good tennis but also some ordinary stuff at times,'' he said. ''Yeah, if you play against a player, you know, like a Kyrgios or Dimitrov or Raonic and those guys and you don't play very well, it's tough to win those matches now, whereas before maybe when they're younger and a bit inexperienced you can still find ways to come through them. But now that they're getting more experience and improving, it's tough to do that.''
That means Murray will be training harder in an attempt to keep up.
''I need to get on the practice court soon, because now there's time before the next bunch of tournaments to do that, to make improvements,'' he said. ''But I'll also need to have a think for a few days about how it is I'm going to go about that, how it is I'm going to go about improving.''
He will also need to decide whether to keep working with new coach Amelie Mauresmo, who was signed on through the grass-court season. The 27-year-old Murray said the two would discuss the relationship during the next week, but indicated he would like the Frenchwoman to keep being part of his team.
''It has to come from both sides. I've really enjoyed the last couple of weeks—I've found it good fun. I found it calming. Tactically, you know, I feel like the chats have been good,'' he said.
Murray is expected to fall to No. 10 in the rankings following this tournament.
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