By Caroline Cheese
BBC Sport at Wimbledon
Andy Murray says he will leave Wimbledon in the knowledge that he can compete with the world's best.
"The support when I walked off Centre Court made me feel like I belonged there," said an exhausted Murray after a five-set defeat by David Nalbandian.
"I want to play in big tournaments and I have proved to myself that I can.
"But it's not about doing it for one week of the year, it's about doing it for 30 weeks. I'm not there physically yet but my tennis is."
After establishing a two-set lead, Murray began to look tired in the third set and that allowed Nalbandian back in.
The 18-year-old, who was treated on court for cramp before the fifth set, said: "I couldn't move towards the end.
"I was annoyed I couldn't keep going in the fifth set. I felt I was running around OK in the fourth, but in the fifth, I really started to feel tired.
"When I got back in the locker room, my legs were so tired I couldn't get up. I just got tired because I've never played a five-set match before.
"I wasn't expecting to do so well so I have to look at it positively. In a few days I'm sure I'll realise what I've done and I'll be proud of myself."
Murray was roared on by a capacity crowd, including fellow Scot Sir Sean Connery, on his Centre Court debut.
He said: "I've just heard that Sean Connery was going nuts in the Royal Box when there was an overrule.
"To play on Centre has always been a dream and the noise was unbelievable."
Murray is entered in the mixed doubles at Wimbledon with Israel's Shahar Peer and afterwards plans to play in the ATP grass-court tournament in Newport.
The teenager said he was ready for the extra attention that would come his way.
"I think my life will change quite a lot," he said. "But maybe it deserves to because I did very well.
"Not every 18-year-old gets to the third round in their first Grand Slam and takes an ex-finalist to five sets.
On dealing with the expectations on his shoulders, he added: "I just have to try and do it.
"There's not much I can do. Everyone can say what they want but I've just got to concentrate on what I'm doing on the court."