Rory McIlroy ended the opening day of the DP World (European) Tour PGA Championship five shots off the lead after finding water on the last hole at a rainswept Wentworth on Thursday.
The world No 2, fresh from his thrilling play-off win in the Irish Open last weekend, is set to be a key figure when Europe defend their Ryder Cup title against the United States at the Bethpage Black course in suburban New York later this month.
It looked as if the Northern Irishman was carrying on from where he left off at the K Club after his first tournament win since completing a career Grand Slam of major titles at the US Masters in April.
McIlroy chipped in for a birdie on the first hole at a tournament he won in 2014 before recording three runner-up finishes in his last five visits.
A second birdie followed at the par-five fourth only for McIlroy to bogey the subsequent par three.
But birdies on the 10th, 12th and 16th strengthened his position only for McIlroy's approach at the concluding par-five 18th to find the water.
The 36-year-old McIlroy was forced to settle for a bogey and a three-under-par 69 as he completed his first round in near darkness at 7:30 pm local time (1830 GMT) following a rain delay of some 90 minutes midway through the afternoon's play.
Ten groups will have to complete their opening rounds on Friday morning.
Sweden's Ludvig Aberg – a captain's pick by Europe skipper Luke Donald for the Ryder Cup – and France's Tom Vaillant share the overnight lead after they both shot eight-under-par 64s.
"I felt like once I got on the greens, I was rolling the putter really nice and tried to be aggressive with the speed," said Aberg. "I managed to make a lot of putts, which is nice."
South Africa's Casey Jarvis is alone in third place following a seven-under 65.
England's Matt Fitzpatrick, another of Donald's six selections, is just two back after a six-under 66, with Ryder Cup veteran Justin Rose a shot further adrift following a bogey-free 67.
Shane Lowry carded five birdies in his final seven holes to join Rose on five-under par, with 11 of Europe's 12 Ryder Cup players involved in the first round at Wentworth, southwest of London.