World number one Rory McIlroy said he is happy to be in the mix after catapulting himself into contention at the halfway stage of the Charles Schwab Challenge.

McIlroy carded a stunning seven-under-par 63 to be two shots behind leader Harold Varner III following Friday's second round in Texas.

Playing without fans at Colonial Country Club in the PGA Tour's first tournament since the coronavirus pandemic suspended the season in March, McIlroy moved into a tie for fourth position thanks to an eagle and six birdies.

McIlroy – a four-time major champion – is nine under alongside Collin Morikawa (67) and Xander Schauffele (66), and a stroke adrift of Jordan Spieth and Bryson DeChambeau.

"You can do as much practice as you want and play as much as you want at home, but until you actually get into that competitive environment, you're never 100 per cent sure of how your game is," McIlroy said.

"I learnt a lot yesterday and I feel like I made some improvements today on yesterday and learnt a few things. So no, not surprised. I've been playing well at home and I've been hitting the ball the way I've wanted to, just a matter of getting it to translate out on to tournament play, and it's nice that it has.

"This is a golf course that's always let the best players rise to the top. You have to be in complete control of your game, hit fairways, hit greens, convert some putts, and yeah, the leaderboard is a who's who of golf right now. I'm just happy to be in the mix."

Former world number one and three-time major champion Spieth impressed with a five-under-par 65 in round two in Fort Worth.

Spieth has struggled for form – his last tournament victory came in 2017. The 26-year-old has posted just 11 top-10 finishes since the start of the 2018 season to drop out of the world's top 50.

But Spieth's revival continued on Friday after back-to-back 65s to be within touching distance of Varner heading into the weekend.

Spieth, who recorded eight birdies, said: "I felt like I gave myself some grace to say, 'Look, I haven't really been practicing a ton of those kind of short-range putts'.

"Those are the ones where you just have a ton of them when you're playing in competition, but you're picking them up a lot of times when you're playing regular rounds of golf at home."