Andy Murray has confirmed he will not be competing in either singles or doubles tennis at this month's US Open.

The former world number one, who will face brother Jamie in the men's doubles quarter-finals at the Cincinnati Masters, had been scheduled to play doubles in New York.

But he has opted to focus on singles competition elsewhere as he bids to step up his return from the career-saving hip surgery he underwent in January.

"I'm not going to play doubles at the US Open," Murray told BBC Sport.

"My goal is to get back playing at the level that I want to on the singles court, and I've decided that I need to focus all my energies on that right now.

"The US Open, doubles and mixed, can be another couple of weeks that you are slowing things down."

Murray and partner Feliciano Lopez beat Ryan Harrison and Jack Sock 2-6 6-3 10-7 to reach the last eight in Cincinnati after Jamie and Neal Skupski overcame French pair Nicolas Mahut and Pierre-Hugues Herbert 6-3 6-3.

Murray will play in next week's ATP event in Winston-Salem after being given a wild card and will then consider entering a tournament on the Challenger Tour during the US Open, which starts on August 26.

In the Cincinnati singles, Roger Federer suffered a shock loss to Russian qualifier Andrey Rublev in the third round.

Rublev, the world number 70, broke Federer three times as he powered to a stunning 6-3 6-4 win in 62 minutes.

The defeat was a blow to 20-time major champion Federer's US Open preparations.

Rublev will now play compatriot Daniil Medvedev in the quarter-finals after the biggest win of his career.

World number three Federer said on www.atp.com: "He was super clean – defence, offence, serving well. Didn't give me anything. He was everywhere.

"So it was tough for me, but an excellent match by him. I was impressed."

Meanwhile, Novak Djokovic beat Pablo Carreno Busta in straight sets, 6-3 6-4. Djokovic will next play Lucas Pouille in the quarter-final.