San Francisco Frontiers - McIlroy and Lowry in the hunt at PGA Zurich Classic

The pair, who are expected to represent Ireland in July's Paris Olympics, share a four-way lead after Friday's alternate shot second round.

After shooting 62 in Thursday's four-ball (better ball) opening round, McIlroy and Lowry carded a two-under-par 70 in tricky wind conditions at TPC Louisiana.

The American pairs of Davis Thompson and Andrew Novak and Ryan Brehm and Mark Hubbard, along with the Anglo-American team of Aaron Rai and David Lipsky were also on 131 after the first two rounds.

Playing the back nine first, the Irish pair reached the turn at one-under before making a bogey on the par-3 third, but they rallied at the end of their round with birdies on the seventh and eighth.

McIlroy said the pair had been able to get the best out of each other's skill sets.

"Shane has got a wonderful short game, and it gives me confidence going for those greens whether it be the par-4s or the par-5s that if I get it anywhere up there around the green, I'm going to have a very good look for birdie after he hits his," McIlroy said.

Rai said he and Lipsky had taken a cautious approach given the conditions, hoping they can take full advantage of the better ball round on Saturday.

"I think we were definitely a little more on the conservative side, and I think the conditions played a part in doing that in some tough pin positions, but we hit some good shots out there," he said after Friday's two-under round of 70.

"Some really good up-and-downs. Dave made some great putts just to keep the momentum going. So we stuck in there really well today and hit some good shots when we needed to. I think anything under par today is a pretty good score," he said.

"I think it's a little bit dependent on the conditions tomorrow," Lipsky said. " It's supposed to be a little breezy, but four-ball is the day you make up ground, make a ton of birdies and try to give yourself a little bit of a cushion. I think that's our main focus."

The American pairing of Patrick Cantlay and Xander Schauffele looked like they might join the quartet at the top of the leaderboard but had to settle for being a stroke off the lead after they bogeyed the 18th.

C.Lewis--SFF