Mark Calcavecchia defied the afternoon rain to shoot a bogey-free 68 and take a three-way share of the first-round lead at the Senior British Open on Thursday.
Bidding to become the fourth player to win both the British Open and the senior version, the 51-year-old American fired two birdies either side of the turn before parring the final five holes in what proved a testing closing stretch for the 144-strong field.
Calcavecchia, winner of the British Open at Troon in 1989, was joined on 4 under by Ireland's Mark McNulty and Australia's Mike Harwood, who earlier benefitted from still and dry conditions on the parkland course at Walton Heath that hosted the 1981 Ryder Cup.
"The weather moved in when we were on No. 11 -- it wasn't horrible but it made it tougher for sure," said Calcavecchia, one of three players not to drop a shot in their first rounds. "Not making any bogeys was nice, so it was a good score, a good start."
South Africa's David Frost and unheralded Scot Albert MacKenzie were a shot behind, with defending champion Bernhard Langer of Germany one of seven players on 2 under.
Three-time winner and eight-time major champion Tom Watson shot a 75, which included a double bogey at No. 8 after finding the middle of the fairway off the tee, to lie seven shots off the pace.
"I wasted a lot of strokes on the greens today. I made two putts, that's about it," the American great said.
After Gary Player and Bob Charles, Watson is the other player to have done the British Open double.
"It's a bit early to talk about that," Calcavecchia said. "We'll give it all we got and see where we're standing on Sunday coming down the stretch. Hopefully I'm there with a chance."
Calcavecchia faded after a solid start at last week's British Open at Sandwich -- shooting a 79 after an opening-day 69 to miss the cut -- and has spent his days off firstly in Paris and then sightseeing in London, taking in Harrods department store and Wimbledon.
Appearing fresh, he birdied the par-5 No. 2 and picked up three more shots in six holes around the turn.
"I will do better here than I did on Friday last week," he said. "Especially hitting irons into the green, this is a lot more like what we are used to playing in the States."
Both McNulty and Harwood finished runner-up at British Opens in the early 1990s but made early moves to go one better in the senior tournament, firing 12 birdies between them before the showers and gray skies descended.
The Zimbabwean-born McNulty marred an otherwise flawless round with a bogey on the par-4 No. 18, while Harwood -- in the following group -- made seven birdies but dropped shots at Nos. 16 and 17.
McNulty, an eight-time winner on the Champions Tour who lost a three-man playoff to Loren Roberts in the 2009 tournament at Sunningdale, said his late bogey took the gloss off his round.
"I made a mental error," said McNulty, who drove into the thick heather on the left side of the fairway. "I'm annoyed with myself but I would've taken 68 on the first tee."
Harwood, runner-up to compatriot Ian Baker-Finch at Royal Birkdale in 1991, was leading on 6 under before successive bogeys halted his charge.
The 52-year-old Australian was otherwise at home on a course where he won the European Open in 1991, one of five European Tour victories before quitting the sport in 1995 following a run of bad results.
"I got some good vibes from this place. I have been thinking about coming back here for a while and I felt comfortable, although I was walking along the edge of the cliff on those last three holes," he said.
MacKenzie only qualified for the event on Monday but birdied the last to lift himself above some of the star names on the senior circuit who are chasing the $310,000 first prize.
"When I saw my name up there with some players I've got so much respect for, it was just wonderful. It's the greatest day of my golfing life by a landslide," said MacKenzie, who won a regional event at Walton Heath back in 1985.
One of those star names MacKenzie finds himself leading is Langer, a two-time Masters champion who is looking to become the first player to defend the Senior Open title since Christy O'Connor Jnr. in 2000.
The German great was 4 under after seven holes but acknowledged the "wheels fell off" when he bogeyed three out of four holes at the start of the back nine.
"I never made any putts from distance ... and I'm still battling with my swing, not totally trusting everything yet," said Langer, who is on the comeback trail after four months out following thumb surgery.
Three Americans -- Bob Tway, Mike Goodes and Lee Rinker -- were among those level with Langer.