Justin Rose explains how he transformed game to lead Charles Schwab Challenge with Harold Varner

Justin Thomas is just one shot back while Rory McIlroy and Brooks Koepka are five behind heading into day two

Rose grabbed the lead on day one in Texas (Getty)

Justin Rose insists he used golf’s break due to coronavirus to polish his game after carding a blemish-free round of 63 to take the joint-lead alongside Harold Varner III in the first major tournament since the coronavirus pandemic shut down the sport.

The world No 14 was the early clubhouse leader in Fort Worth, Texas, capitalising on an early start before American Varner drained an 11-foot putt on the 18th to join him on seven under.

Just a shot back are Venezuelan Jhonattan Vegas, Mexico’s Abraham Ancer and Americans Collin Morikawa and Justin Thomas, both of whom thrilled late on day one.

Dustin Johnson was a disappointment though as the former world No 1 was slow out the blocks on his way to a one-over 71, which included four bogeys.

There was joy for England’s Ian Poulter though, with the Ryder Cup star in a tie for 16th place after a round of 66 while Phil Mickelson – fresh from his challenge matches with Tiger Woods during the shutdown – could only manage a one-under 69 to sit in a share of 57th place.

The event is the first on the PGA Tour since the Arnold Palmer Invitational in Orlando, Florida in early March, and has drawn a star-studded field to Texas.

Sixteen of the world top 20 will be in action over the weekend, and top-ranked Rory McIlroy’s round of 68 was good enough for a share of 39th place.

Rose said a bit of luck on the opening hole had set him on his way as he overcame some wayward shots to birdie his first hole.

“I got some momentum,” he said on Sky Sports Golf. “I didn’t play particularly well on the first six or seven holes but the putter was really hot.

Varner tied for the lead after day one (Getty)

“I got into a nice rhythm and I could have maybe got in the clubhouse better but I rode my luck a little bit.”

Rose felt the performance was reward for the work he managed to do during the hiatus.

“I’ve worked hard for sure,” he said. “I haven’t just sat around. I had the opportunity to get better. My season wasn’t going particularly well up until the Players Championship so you try to look at the positives.

“Obviously it’s been a tough situation for everybody across the world, there are some dire circumstances, but you’ve got to look at yourself, your personal situation, and think, ‘How can I make the most of this?”’

PA also contributed to this report