Jamie Murray showed a flash of both ambition and ruthlessness yesterday by splitting from his doubles partner, Eric Butorac.

The 21-year-old from Dunblane will play his last tournament with the American at the US Open, which starts on August 27, having decided that his promising career would be better served with a different partner.

"I was ready to move on," said Murray, who won three ATP Tour titles this year with Butorac before dissolving a partnership which currently stands at No.13 in the world team rankings.

"I initiated it because I wasn't really feeling it anymore and I thought it was best for me to try and find somebody else to play with."

Despite the success of team dubbed Booty and Stretch', a poor run of results since Wimbledon, where Murray showed his individual talent by winning the mixed doubles title with Jelena Jankovic, compounded growing problems on court.

"We haven't fallen out or anything like that," said Murray. "If it wasn't for Eric I wouldn't have moved up to the ranking I have and I probably wouldn't have three titles to my name this year, so there is a lot to be thankful for. It's just one of those things."

Finding a new partner mid-season could be difficult and Murray may have to wait until the end of the year, when existing teams are more likely to break-up and when it will be easier to find a partner accomplished enough to help him improve his doubles game and ranking. Roland Garros champions Mark Knowles and Daniel Nestor are planning to split up later this year and either man would fit the bill perfectly.

"If I had the opportunity to be on the court with guys like that who have got to No.1 in the world and won grand slam titles then I'd obviously love to do that," said Murray.

The Scot's immediate problem is finding a partner for the swing of tournaments leading into the US Open, starting with next week's Canadian Masters and including the Cincinnati Masters and the Pilot Pen in New Haven. His brother, Andy, is scheduled to play all three events and might oblige, especially since he will be returning from a lay-off of nearly three months with a wrist injury and could do with as much time on court as his wrist can handle. Beyond that, Jamie Murray will look for other temporary solutions until the right long-term partner becomes available.

Meanwhile, Tim Henman's miserable year continued as he failed recapture his glory days at the Legg Mason Tennis Classic in Washington, going down to John Isner. The American wild card ousted him 4-6, 6-4, 7-6 (7-4) in the first round of the £300,000 hardcourt event.

Henman defeated Fernando Gonzalez to win the event in 2003, the last year he hoisted a championship trophy. He also won in Paris later that year but has appeared in just two finals since, losing on both occasions to the world No.1, Roger Federer.

Henman, 32, put up a fight before finally falling to the 22-year-old, who is ranked 419th in the world. Trailing 5-4 in the third set, Henman faced match point at 15-40 but reeled off four consecutive points to remain in the tie.

Paisley's Elena Baltacha is out of the women's tournament after losing to the second seed. Olga Savchuk. The Scot won the first set 6-3 but lost the next two by the same scoreline.