Andy Murray admitted he was "jealous" of watching his old rivals Novak Djokovic and Rafael Nadal duelling at the French Open, and then gave a pessimistic assessment of his chances of ever rejoining them at the top.
Djokovic overcame Nadal in four high-quality sets in the semi-finals at Roland Garros, before claiming grand slam title number 19 against Stefanos Tsitsipas on Sunday.
Three-time grand slam winner Murray, preparing for his first singles outing on grass in three years at Queen's Club this week, says his tennis is in good shape.
But with Wimbledon just around the corner, the 34-year-old Scot remains unsure whether his body will hold up following the fitness issues which have dogged him later in his career.
He said: "I feel OK. I don't feel perfect, but I've been practicing well over the last month or so, pretty consistently. I have been training at Wimbledon, and we came out here the last few days and had a couple of good practices.
"The question mark is obviously whether the body holds up and I can't say with any great certainty right now whether that's going to happen or not, because I have been feeling good at different points throughout the last nine months or so, practiced really well, felt good going into tournaments. Then, you know, something's happened.
"I can't say with any great certainty I will be OK. I mean, I hope I will be, because I'm sure and I have seen enough again in practice that my tennis is fine and in a good place, but, physically I need to hold up under playing matches."
Murray faces France's Benoit Paire on Tuesday at the Cinch Championships, the scene of five singles titles and an emotional doubles win with Feliciano Lopez in 2019, on his comeback from hip surgery.
He added: "I got asked yesterday in an interview what was my best memories of Queen's, looking back.
"The first memory, maybe because it was most recent, but I don't think it was because of that, but winning the doubles at Queen's with Feli. For me it was really special, and I still created a memory and something I will look back on and be very proud and look back on fondly.
"You know, you can still do things on the court outside of winning slams or competing with those guys.
"In terms of that (semi-final) match, it was an incredible match. You know, there is a bit of me that's jealous watching that, like I would love to be playing in those matches.
"I would love to still be competing with them in semis of slams, I would love that. I'm not going to try and hide that. But I don't look at that match and think about my own career really."