Shaun Micheel carded a five-under 67 to grab a one-stroke lead after the opening round of the Open de Espana.

Micheel is making his third European Tour start of the year. He shared 25th in Qatar, then missed the cut in Dubai.

Robert Rock posted a four-under 68 at Real Club de Golf de Sevilla and was joined in second place by Danny Willett and Jorge Campillo.

Matthew Baldwin is alone in fifth place at minus-three, while Francesco Molinari shot two-under 70. He stands alongside Gary Orr, Graeme Storm, Rafael Cabrera-Bello, Sam Hutsby and Matteo Manassero in a tie for sixth.

Molinari was one of just five players who broke par in the tougher conditions earlier on Thursday, when it was windy and raining. As conditions improved, only 16 more players broke par in the afternoon wave.

Micheel, the 2003 PGA Champion, played alongside a pair of fellow American major champions. He was paired with 2005 U.S. Open winner Michael Campbell (75) and 2002 PGA Champion Rich Beem (78).

Despite his partner's struggles, Micheel climbed his way to the top of the leaderboard. He birdied the first, but gave that stroke back on the second.

The 43-year-old came right back with a birdie on the third. Micheel converted back-to-back birdie chances from the fifth.

Micheel faltered to another bogey on the eighth. He quickly got that stroke back with a birdie on No. 9.

Around the turn, Micheel birdied three of four holes from the 13th to grab a two-stroke lead at six-under. His birdies on 13 and 15 were from inside five feet, while he two-putted from 25 feet at the 16th.

Micheel stumbled to a bogey at the last after his tee shot and second shot both found sand. He two-putted for bogey to cut his lead to one.

"I didn't expect this. Yesterday, in the pro-am, I didn't make any birdies, and it wasn't for lack of effort, I can assure you," Micheel said. "I had a terrific start with four birdies on my first six holes. I think the key was I kept the ball in play, made a couple of nice putts, and I made all my short putts.

"My iron play was good and I just managed myself well and gave myself a lot of opportunities. Outside my bogey in the last, I'm extremely pleased."

Rock, who beat Tiger Woods in the final round in Abu Dhabi earlier this year, birdied the second, but dropped shots on the next two holes. He atoned for those mistakes with birdies on five and six.

After a pair of pars, Rock birdied the ninth to make the turn at two-under. He eagled the 13th, but struggled to a bogey on the 14th. Rock made another eagle, on the par-five 16th, to grab share of second.

Willett played the front nine in even-par with two bogeys and two birdies. He flew up the leaderboard on the back nine with three birdies in the first four holes. He got to minus-four with a birdie on the 16th, then parred the final two holes.

Campillo, who is the leading Spaniard by two strokes, opened with a birdie on the first. After carding back-to-back birdies from the fifth, he ran off 11 consecutive pars from the seventh. Campillo capped his bogey-free round with a birdie at the 18th.

NOTES: Defending champion Thomas Aiken posted a one-under 71 and is tied for 12th...World No. 36 Simon Dyson, the highest-ranked player in the field, also carded a 71...Just three Spaniards who broke par in the first round.