Rusty Rory McIlroy is eclipsed by Lee Westwood's magic putter

Quick on the draw in deepest Texas. Lee Westwood went with his new shooter to upstage Rory McIlroy on the opening day of the Shell Houston Open. Westwood has been wrestling with the putter in recent years, leading to the introduction of the Ping Nome, a flat stick with an adjustable shaft that allows the Englishman to lengthen the instrument without anchoring.

The result was an opening 68, five better than McIlroy, who was as slow off the mark as Westwood was quick. Three birdies in the opening five holes and four in five on the back nine might have seen Westwood nudging leader D A Points on eight under, but a failure to master the par-fives undermined his card.

"I must have the worst par-five record on the PGA tour this year," Westwood said. "It should have been a 64. My short game and pitching are really good, so there's no reason why the par-five scoring shouldn't sharpen up when you play like that and shoot 68, you make two sixes on a par five instead of making four. That's giving up four shots."

That will come. Westwood hits it too cleanly not to solve the par-five anomaly, especially if the putter continues to behave. "It's about four inches longer than standard. It just helps me to swing the putter a bit easier. It worked well today. I've been practising with it for a while, but it's just in the last couple of weeks that I've felt comfortable enough to take it on the course. I holed it from 18 feet on two, 10 feet on three, 20 feet on five, 20 feet on 14, probably 18 feet on six."

McIlroy, needing to win here to regain top spot in the world rankings from Tiger Woods, looked woefully undercooked, dropping a shot at the second and two at the par-five eighth in what was only his ninth round of the year. Then, hey presto, McIlroy suddenly found his mojo with four birdies in six holes to stabilise if not ignite his round.

"I felt like a hit the ball ok. I just need to eliminate the silly mistakes," the Northern Irishman said. "I'm still a bit tentative out there, not quite committing to some shots, but three more competitive rounds and hopefully I'll be in good shape for the Masters."

Marcel Siem's hopes of making the world's top 50 and automatic passage to the Masters next month received the boost of an opening 64 in Morocco, where he leads the Hassan Trophy by three shots on eight under par.

Siem needs to leap 22 places to secure his Augusta debut. Playing in the afternoon, he enjoyed the better of conditions that blew the early starters all over the place, and in the case of Jakob Svoboda, off the course for good. More than 30 players carded 80 or worse. Svoboda decided enough was enough after six holes, retiring on 21 over par.

It helps when you chip in twice at the last two holes. "Sometimes you need a bit of luck in this game and thankfully today was one of those days where it went my way," Siem said. "I didn't know I still had a chance for the Masters but now we know there are four or five of us in the field here who still might be able to get to the Masters if we win.

"It is a nice incentive but I came here first and foremost to play this tournament. The Masters would be special but I just have to concentrate on what I am doing in this tournament."