Andy Murray & Feliciano Lopez lose to Jamie Murray & Neal Skupski at Cincinnati Masters
Andy Murray will switch attention back to his singles comeback after losing to older brother Jamie in the Cincinnati Masters quarter-finals.
In the second meeting of the Scottish brothers' careers, Jamie Murray and Neal Skupski beat Andy Murray and Feliciano Lopez 6-7 (5-7) 7-5 10-4.
A tight match went in favour of the doubles specialists when Lopez, 35, lost his way on serve.
Murray and Skupski face Ivan Dodig and Filip Polasek in the semi-finals.
"It was tough, not the most enjoyable match. The atmosphere kind of felt a bit flat on the court which I think is in some ways normal in those sorts of matches," said Andy Murray.
"But it was fine, and I'm happy Jamie got through. You want to go out there and compete and play as well as you can, but you're not getting the same enjoyment out of serving an ace or hitting a great return as you might be in other matches.
"Obviously we tried to do our best but it wasn't enough today."
Both Andy and Jamie, who played together in Washington earlier this month, said it would be a "weird" feeling playing against each other in a competitive scenario and the match ended up lacking intensity.
A double fault from Lopez swung a second set, which saw just one receiving point won in the opening seven games, in the favour of Jamie Murray and Skupski and the Spaniard produced two more in a one-sided first-to-10 match tie-break.
Of playing his brother, Jamie said: "It was a bit awkward, but it wasn't as bad as I thought it was going to be. It was probably harder for him to be honest, but we both went out there and battled hard.
"You're looking across the net 99% of the match so you're constantly seeing your brother but honestly it wasn't too bad. Just kind of head down and play and focus on the ball and not overthink things too much, and obviously happy to win in the end."
Andy Murray will play singles at next week's ATP event in Winston-Salem before considering entering a tournament on the Challenger Tour during the US Open.
The former world number one, who had career-saving hip surgery in January and made his singles comeback on Monday, will not play at Flushing Meadows later this month.
The 2012 champion had intended to play doubles in New York but said "doubles is done for me for the time being".
The 32-year-old has taken the final wildcard for next week's event in Winston-Salem.