Updated

Louis Oosthuizen and Brian Davis went well under par during their second rounds Friday to tie for the lead at the Houston Open, which is still behind schedule because of weather.

A big storm hit the tournament Thursday, causing a long delay and prompting officials to halt play. The first round was completed Friday morning, but many still need to complete their second rounds.

The tournament will resume at 8:30 a.m. (ET) on Saturday.

When play was stopped at 8:36 p.m. (ET) Friday evening, Davis and Oosthuizen were knotted in first at 11-under-par 133. Davis carded a seven-under 65 with the lift, clean and place rules in effect for round two. Oosthuizen, the 2010 British Open champion, posted a 66.

Jeff Maggert is alone in third at 10-under, though still has eight holes to go in his second round. He was four-under through his first 10.

Defending champion Phil Mickelson was one of three first-round leaders after finishing a 65 on Friday, then went back out and fired a second-round 70.

"I really enjoy it because you can get in a good rhythm if you start striking the ball well, you can get a hot hand and make some birdies," Mickelson said. "I think there's an advantage there to be able to keep playing if you're playing well."

He is tied for fourth at nine-under, along with Tommy Gainey (67), Greg Owen (69) and J.B. Holmes (67). James Driscoll, who was four-under through seven holes, is also sitting at minus-nine.

Davis is a two-time European Tour winner, but hasn't titled since the 2004 ANZ Championship. He has also gone through a multitude of changes since the end of last year, when his father died from cancer.

"It was obviously a tough time for me and time to maybe reassess my life and look at what I'm doing, which I did, and it's been a positive," Davis said.

The 37-year-old said he changed caddies, went to a sports psychologist, worked on his swing, and started to manage his time better between golf and family. He endured a rough start to the season, missing the cut in three of his first four events, but tied for fourth last week at the Arnold Palmer Invitational.

The Englishman will head into the weekend with a share of the clubhouse lead thanks to 32 holes of productive golf Friday.

He carded three birdies and a bogey during the back nine of his first round to reach four-under, then kept rolling.

Davis began his second round at the par-four 10th and knocked his second to three feet, then rolled in the short birdie effort. He repeated the formula at the par-five 13th, where he stuck his third within nine feet before sinking the putt. A 12-footer for birdie at the 18th sent him around the turn at minus-seven, but he wasn't finished.

He gained a stroke with a 19-footer at the first, then made birdie putts of eight feet or less at two, six and eight.

"It was a good day at the office today. It was tougher this morning because we didn't have ball in hand to start the round and we had the rain yesterday," Davis said.

Oosthuizen played 33 holes, but was already good position after opening his first round Thursday with back-to-back birdies at 10 and 11.

Once resuming the round Friday, he dipped further under par with three birdies in a row from the second hole. The South African finished with a first-round 67 after a bogey-birdie sequence at seven and eight.

His bogey-free second round included birdies at one, four and eight, which put him at minus-eight. Oosthuizen stayed there around the turn, but was able to match Davis' score thanks to three straight birdies on his back nine.

He drained a 14-footer at the 12th, blasted out of a greenside bunker to set up an 11-footer at the 13th, then hit his tee shot within three feet at the par-three 14th.

Oosthuizen parred out to complete the 66 and remain at minus-11.

"It's a good spot to be in going into the weekend," Oosthuizen said. "I don't know if it will be leading, probably be close. But yeah, I played nicely. I hit my irons very well today, which was both rounds. Struggled a little bit off the tee. Now and then working on something. So, you know, hopefully I've got it spot on next week."

He was referring to The Masters, the season's first major, which starts next Thursday at Augusta National and is looming in the distance.

Mickelson, a three-time Masters winner, will enter the tournament as one of the favorites and appears to have his game in good shape. He carded 11 birdies and three bogeys during 33 holes Friday.

One player who is likely not to appear at Augusta is Ernie Els, who needs to win in Houston to gain entry to The Masters. He is sitting at five-under, six strokes off the lead.

NOTES: Defending Masters winner Charl Schwartzel is in danger of missing the cut, which is currently projected to be two-under. He is one-under after stumbling to a second-round 74...Anthony Kim, the 2010 Houston Open winner, withdrew. Other withdrawals included Chris Couch, Matt Bettencourt and Spencer Levin...Fred Couples, sitting at four-under, is set to make the cut for the 19th consecutive time at this tournament, matching Jimmy Demaret's event record.