Bryson DeChambeau remains on course for a successful defence of his title at the Omega Dubai Desert Classic after a fine 67 on Friday. The American, who triumphed last year with a tournament record 24-under par, began the afternoon with three birdies at Emirates Golf Club and added another four, although he did drop shots at the sixth and the 15th. At the halfway point, DeChambeau sits on 7-under, one stroke behind leader Eddie Pepperell, who earlier in the day matched the defending champion's second-round score. Sweden’s Robert Karlsson and Dean Burmester of South Africa join DeChambeau in joint second, with another 10 players within four shots of the lead, including world No 10 Tommy Fleetwood. Aged 26, DeChambeau has put on considerable weight during the off-season in a bid to add length to his game. That was evident on the par-5 3rd, when his drive measured 375 yards, 70 ahead of playing partner Henrik Stenson. On the par-4 17th, he drove the green before the ball nestled in the rough. “It's opened new boundaries that I never thought were possible, to be up front with you,” DeChambeau said. “I don't know necessarily how to control all of it yet, but I'm getting to the place where I'm starting to learn what driver what I need, under the gun, in certain conditions – a left-to-right wind, a left-to-right wind – what to do and how to apply that power to allow me to have more scoring opportunities. So it's a gigantic leap for me.” Previously criticised for being one of the slower guys in golf, DeChambeau has resolved to speed up his game. In Abu Dhabi last week, where he eventually missed the cut, playing partner Matt Fitzpatrick commended the world No 17’s quickened pace of play. “I would say it's just getting more comfortable on the golf course, recognising the fact that I'm not perfect, I make mistakes and I made mistakes in the past, but working on improving everything,” DeChambeau said. “That's my whole goal for the game of golf: is not only to make myself a better player, but to have people have a more enjoyable experience when I'm around. And that's really what I'm trying to do and provide people with, so I don't bother anybody on the golf course – that's the last thing I want to do. And so I made it a point to work on it and I've gotten a little bit better. And I think it shows.” Asked what score might be enough to win this week on a toughened Majlis Course, DeChambeau said: “I'll take what the course gives me. If it's the same conditions I think 16-, 17-under will definitely get the job done.” Pepperell is about halfway there following an excellent 67 on Friday. The Englishman, with two wins on the European Tour under his belt, set the early pace in the morning, registering six birdies and one bogey through his first 13 holes. A bogey on 15 looked to stunt his progress, but he responded with birdies on his next two to post the clubhouse lead. “I was happy with how I was feeling early and I got off to a nice start,” Pepperell said. “For the most part it was very, very good until the cameras came along. I must have been concerned with how I was looking, because then I started struggling.” The last time Pepperell held the 36-hole lead at a tournament he went on to seal the British Masters, in October 2018. “It's where I want to be,” he said. “I think me and [caddie] Mick [Doran] as a team out there do all the right things to make me quite difficult to beat if I'm in that position. So that's something I've enjoyed in the past and I'll keep on doing it. And I would hope that that would be the same this weekend.