Andy Murray's first match of the grass-court season ended in defeat by American Marcos Giron at the Stuttgart Open.

Appearing in the 999th singles match of his career, three-time Grand Slam champion Murray was beaten 6-3 6-4 in the first round.

The 37-year-old is preparing for what looks set to be his final Wimbledon, having previously said he does not plan on "playing much beyond the summer".

"I've had some tough months, but physically I feel OK just now - the ankle, the back. It's all felt better since going on to grass," said Murray.

Against Giron, the former world number one twice saved break point in his first service game, before missing out on an early chance to break himself.

World number 54 Giron soon took advantage, breaking to go up 4-2 before taking the opening set comfortably.

Murray rallied at the start of the second set, holding to love in the first game before going 40-15 up on his opponent's serve.

But he failed to convert his break points, with Giron instantly getting a break of his own that he did not relinquish.

"I've been struggling with breaking serve. I've not broken for a few matches and that's usually been a strength of mine," added Murray.

"On a quick surface like grass, the sets are tight. When your chances come you have to be clinical - he was and I wasn't."

Giron, 30, will face another Briton, sixth seed Jack Draper, in the second round on Wednesday.

Murray hopes to play at the Cinch Championships at Queen's next week as his preparations continue for Wimbledon.

He will also team up with brother Jamie in the men's doubles at the All England Club in what will be their first Grand Slam appearance as a pair.

Earlier this month, Jamie Murray told BBC Sport it was "now or never" for the brothers to play together.

Wimbledon starts on 1 July.