Watson, the field’s top-ranked player, shot closing rounds of 65 and 66 at Genzon for the past two years and fulfilled his aim to start as strongly as he usually finishes as he seeks his second European Tour win in China.

“Now I’ve just got to hope I don’t finish like I usually start,” joked Watson, who won the 2014 WGC-HSBC Champions in Shanghai.

“I’m pretty happy with six-under. All in all, a great day and a good start, especially as we thought it was going to rain. I hit a lot of good shots and a lot of greens, so it took away the chance to make the mistakes I made in the past.

“I’ve been working so hard with my putting on getting more speed and getting the ball to the hole, to at least give it a chance to go in. That’s what I did better this first round compared to the last couple of years here.”

Teeing off on 10, the big-hitting American bogeyed 12 but then picked up six shots in the next eight holes, following up birdies at 13, 14, 16 and one with a spectacular eagle on the 547-yard par-five second.

After a solid tee-shot, the left-hander faded his approach ‘about 30 yards’ around the trees and across the water, before nailing the putt to move to five-under and take over as leader from Fleetwood, who bogeyed the same hole. Watson later birdied the par-five ninth to finish with a 66.

“On two, I hit hybrid off the tee as it was downwind and I wanted to stop short of the water. I think it was 253 to the hole, so I hit a big ol’ sliced three-wood around the trees to about 10 feet and then got it to go in,” said Watson, who’s playing with Li in the tournament’s opening rounds for the third straight year.

“It’s fun playing with him – I’ve played with him a few times here. What a good kid – and he is a kid; he’s only 21. It was good to see him again and hang out. He was unfortunate to be sick yesterday and he was still sick today so it was great that he came out and played.”

Watson, whose nine PGA Tour wins include Masters wins in 2012 and 2014, has lost over 15 pounds after embarking on a healthy diet this year, but the father of two said the big change to his game followed putting advice from former Ryder Cup teammate Brandt Snedeker.

“My putting was awful at the start of the year so at the [WGC] Match Play, Brandt Snedeker told me a few things I was doing wrong and that he would like to see me do better. The new stroke has helped a lot with consistency in my roll,” Watson said.

“When I got to Shenzhen, I already knew what the greens were going to be like, so it was taking that same stroke since Match Play and getting better with it. Over time, it’ll get better and better. I’m doing the right things now.”

Fleetwood, the field’s second-ranked player behind Watson, briefly led after carding four birdies in his first five holes and is among the pre-tournament favourites after finishing third in 2015 and runner-up at the 2014 Volvo China Open held at Genzon.

“Playing with Bubba, who shot six-under, makes my score feel worse than it is, but it’s still a good start,” said Fleetwood, who won January’s Abu Dhabi HSBC Championship and finished second to Dustin Johnson at last month’s WGC-Mexico Championship.

“I hit it pretty good most of the day and had a lot of chances. When you start like I did, you think you’re going to hole everything and then when you don’t, it gets frustrating. But breaking 70 around here is a good round.”