Valderrama is a fickle temptress; beguiling one moment, but ready and able to spurn the next. Yesterday, as the Volvo Masters reached its midway point, Sergio Garcia - in shooting a second round 69 for six-under-par 136, to be one stroke clear of Scotland's Alastair Forysth - embraced its charms to secure the lead in the PGA European Tour's €3.75 million season's finale.

Yet Garcia, of all people, was certain not to be lured into a false sense of security going into the business end of the tournament. Indeed, on a day of some bizarre happenings, which included Darren Clarke recording a sextuple bogey 11 on the infamous 17th hole, the Spaniard had a post-round scare of his own.

Upon finishing his round, Garcia was interrogated by tournament officials about a possible rules infringement, before being allowed to let his score stand and, consequently, his position as leader remain. The issue was complex and could have led to Garcia's disqualification.

This is what happened. On the third hole, a par three of 187 yards, Garcia's original tee-shot was hit so badly awry to the right that it finished up in scrubland. He promptly announced that he was hitting a provisional, which he did - to 12 feet!

Garcia then decided not to search for his original ball and played the provisional. Although he missed his bogey putt, he finished with a double-bogey five.

The complication that arose was that Garcia's original ball had actually been found in time and before he had reached the green. Bizarrely - and this is where it beggared belief - no one informed Garcia that his original ball, lying in an ugly bit of terrain, but inside the course's boundary, had been located.

So, under the rules, he was fully entitled to play the provisional and, once he did so on the green, it became the ball in play.

John Paramour, the chief referee with the PGA European Tour, had been waiting in the recorder's hut when Garcia - unaware that there was a potential problem - completed his round. He undertook an investigation which, as well as studying television pictures, included talking to Garcia, his playing partner, Jose Manuel Lara, their respective caddies, the scorer with the match and Howard Clark, the former Ryder Cup player who was the on-course television reporter with the match.

The critical point was whether Garcia had been informed that his original ball was found and, it seems, Paramour found conclusively that, for whatever reason, nobody had actually told the player that they'd found his ball.

"It's bizarre in the extreme," agreed Paramour of the failure of anyone to make that fact known.

One is inclined to believe Garcia when he remarked afterwards that there was no intention to deceive anyone.

"If I felt like I cheated, I would be the first one not playing tomorrow because I couldn't live with that," he said. "But I don't feel like I have done anything wrong."

Garcia, who has called penalty shots on himself a number of times in the past, including here at the Volvo Masters two years ago when he felt that his ball had moved on the fairway but nobody else saw such movement, admitted that the fact he hit his second tee-shot to 12 feet, giving the chance to make a four - "but, unfortunately, I didn't" - influenced his decision not to look for his original ball.

"But nobody told me, 'we found a ball', not my ball but 'we found a ball' or anything . . . (so) I just wanted to continue playing my second."

As it happened, that double-bogey didn't affect Garcia. And, unaware of any potential problem, he gave himself numerous birdie chances on that front nine without converting any.

On the 10th, though, he had a 25-foot, left-to-right breaking putt that reminded him of his Ryder Cup singles match with Phil Mickelson. "I just got a good thought in my head and knocked it straight in and I thought, 'well, here we go'."

It was to spark a fabulous homeward run that saw him also grab birdies at the 11th, 14th, 17th and 18th holes. On the 17th, he hit a wonderfully brave three-wood approach of 241 yards to 15 feet, only to leave the eagle putt on the edge of the hole. But he rounded off his round superbly, hitting a wedge in to eight feet on the last.

It gave Garcia - after he was given the all-clear from Paramour - a one-shot lead over Forsyth, with Ian Poulter a stroke further back in third place.

In all, only nine players reached the halfway point under par.

For a time, the Irish challenge was gathering to be a strong one. But Clarke's nightmare on the 17th sent him crashing from three-under to three-over in one fell swoop, while Padraig Harrington suffered a double bogey six on the 16th. Still, the Dubliner signed for a 70 for a 36-hole total of level par 142.

"I just lost a little bit of focus on the 16th," said Harrington. "I'd like to be a few better, even one or two shots, but it's very possible to shoot 66 out there. I wasn't far away from it myself today. But I'd like to have myself in a position that if I did shoot 66 it would count . . . what I need is a day when my ball-striking and my putter come together."

Harrington added: "I don't think I've had two phenomenal days and, you know, I'm somewhat in touch. But I'll have to produce some goods at the weekend."

That's especially so if he is to have any chance of catching Garcia, who, it seems, was blessed by the silence of those who did find his ball yesterday.