Andy Murray and brother Jamie battled past French pair Nicolas Mahut and Edouard Roger-Vasselin at the Citi Open in Washington.
The former world number one has so far been restricted to doubles action since returning to the game following his hip resurfacing operation in January, and played in the mixed event alongside Serena Williams at Wimbledon.
Murray, who has suggested his singles return may be closer than he originally thought, produced a composed display alongside his brother as they progressed to the quarter-finals with a gutsy 6-4 6-7 (7) 10-5 win in a tie-break decider.
Meanwhile, Cameron Norrie has been knocked out of the Los Cabos Open in the round of 16 7-5 7-5 by eighth seed Mikhail Kukushkin.
Pairing with his brother was not a new partnership, the Murrays having played together at the Rio Olympics and also formed a prolific partnership during Great Britain's 2015 Davis Cup victory.
Jamie Murray, meanwhile, was looking to defend his ATP Tour title won in Washington last year with Bruno Soares.
The opening set went with serve before the Murray's pressure told in game 10 to gain a crucial break.
The match remained a tight affair as the French pair held on to force a tie-break.
The Murrays saw two match point chances missed, having been 6-4 up, the second with a wide return from the former world number one.
Some more fine returns from the British duo saw another opportunity to break for the match, but again the Frenchmen responded to level at 7-7 before closing out to force a 10-point tie-break decider.
Mahut and Roger-Vasselin then appeared to be in control after moving 5-3 ahead, only for the Murray brothers to respond magnificently and lead 8-5.
Jamie Murray then served for the match, with Andy's crosscourt forehand setting up another opportunity to take a hard-earned victory, which was secured when the return went into the net.
In Mexico, Norrie started strongly against his Kazakh opponent and broke for a 5-4 lead in the first set, but lost his next two service games to go a set behind after 44 minutes.
The second set followed serve for eight games, with both players getting a break as the score reached 5-5.
Kukushkin won his service game for a 6-5 lead and converted his fourth break point to take the match and make it through to the next round.
