Andy Murray fell to a first defeat since starting his comeback in doubles in the first round of the Nature Valley International at Eastbourne.
Murray and Brazilian Marcelo Melo lost 6-2 6-4 to Colombian top seeds Robert Farah and Juan Sebastian Cabal.
The Briton struggled on serve at Eastbourne, being broken three times out of four.
Murray had won the doubles alongside Feliciano Lopez at Queen’s last week in his first tournament since hip surgery.
They defeated Farah and Cabal in the first round of that tournament but the Colombian pairing were always in control at Devonshire Park.
Murray will now head to Wimbledon, where he will partner Frenchman Pierre-Hugues Herbert in the men’s doubles.
After Tuesday’s defeat, he told BBC Sport that he was “most likely” to also play mixed doubles at SW19 but is a little concerned about the wear and tear on his body.
The Scot, 32, had thought he might not play again before hip resurfacing in January left him “pain free”.
“I spoke to some of the doubles players the last few days about why they don’t always play mixed and they just said they had some situations where the weather has not always been so good,” he said.
“And because doubles is best of five [sets], and you play with the advantage scoring, you can get backed up and end up playing four matches in two days. I just need to be certain that my body’s ready for that. So I’ll chat to my team a bit about that and decide probably by the end of
tomorrow, I would imagine.”
Murray is yet to finalise a potential partner for the mixed, having been turned down by singles world number one Ashleigh Barty and Frenchwoman Kristina Mladenovic.
He added: “I’ve spoken to a few of the players the last few days about it, so there’s a few kind of lined up and I said I would let them know in the next couple of days.”