Andy and Jamie Murray lost in three sets to Raven Klaasen and Michael Venus in the quarter-finals of the Washington Open.
The British pair took the first set on a tie-break but lost a second as all 24 games followed serve.
South African Klaasen and New Zealand's Venus, seeded third, trailed 5-7 in the final tie-break but won five points in a row to win 6-7 (3-7) 7-6 (8-6) 10-7.
Andy Murray, 32, is playing his fourth event since hip surgery in January.
The former world number one feared his career might be over before having the hip resurfacing operation, but returned to the doubles court five months later when he won the Queen's title alongside Spain's Feliciano Lopez.