Andy Murray says he played some “encouraging” tennis as he made his return at the Battle of the Brits after seven months out.
Murray, who last played in November before sustaining a pelvic injury, took the first set with ease against British number one Dan Evans in the semi-final.
But the 33-year-old eventually lost 1-6 6-3 10-8.
“I’ve just not been able to sustain a high level for long enough,” Murray, ranked 129th in the world, said.
“My game is there, I just need more time to practise and prepare and I’ll get there.
“Some of the tennis this week has been very encouraging, I just wasn’t able to do it for long enough in the matches.”
Murray won three Grand Slams before undergoing hip surgery in 2018 and the former world number one has struggled to return to form since.
Four matches in five days at the event organised by his brother put his fitness to the test, although a shortened format of two sets and a tie-break is being played.
Murray added: “It was a big step up this week from what I’ve been doing, and I coped with it physically relatively well, I thought I moved better with each match and was a bit more confident. It was a positive week.
“That’s something that, when I was up at the top of the game and competing regularly, my level was the same throughout whereas I’m struggling to maintain that, probably just with lack of matches.”
To reduce the risk of another injury, Murray plans to play only the Washington Open on 14 August before the US Open – which he won in 2012 – on 31 August
The rescheduled French Open, usually played in May, will start just two weeks after the US Open and some players may choose to prioritise Grand Slams over other tournaments in such a packed schedule.
Murray said decision-makers in tennis would have to “think long and hard” about how the rankings system could change to reduce the impact.
Players must defend points they earned in the same event last year, but would not be able to do this if they decide not to play some tournaments.
Murray suggested imposing a temporary two-year ranking system so that players “not able to defend their points properly aren’t punished”.