Colin Montgomerie was relieved to remain in contention for his first strokeplay title on American soil after the second round of the $4.2 million American Express Championship.

Montgomerie added a 69 to his opening 64 for a seven-under-par halfway total of 133 at Harding Park, one ahead of Ryder Cup team-mate David Howell who fired a 67.

World number one Tiger Woods dropped a shot on the 17th to shoot a 68 and finished on five under par.

"I'm glad to get in with a 69," admitted Montgomerie after holing from six feet for a bogey at the 18th.

"After a 64 any score in the 60s is a reasonable effort.

"I'm actually quite tired, the jet-lag is kicking in, so I'm glad to get finished. My confidence is high and that's what is keeping me going. I'm looking forward to playing at the weekend and seeing how well I can do."

Montgomerie, fresh from victory in the Dunhill Links Championship on Sunday, had a three-shot overnight cushion but that was wiped out within 10 holes of the second round in damp, misty conditions.

The Scot had been back to his accurate best in the first round, missing just four fairways and finding 16 of the 18 greens in regulation.

But he was unable to maintain that form in the second round and after going to the turn in 34 with one birdie and eight pars, a poor drive on the 10th cost him his first bogey of the week.

From the heavy rough left of the fairway he was only able to advance his second shot some 85 yards, and from there hacked his third into a greenside bunker from which he took three to get down.

After 27 holes without a bogey it looked as though Montgomerie would make it two in three holes when he duffed his chip to the par-four 12th from just off the green.

But the former European number one rolled in a 12-foot putt to save par and then birdied the 16th and 17th, for the second day running hitting his approach on the latter to within inches of the flag.

All that good work almost came undone on the 18th however. His approach was carved right of the green and his first chip failed to find the putting surface. His fourth shot pulled up six feet short but the 42-year-old bravely holed for a bogey five.

"I got off to a good start, it went flat in the middle and then I got it back on 16 and 17 and nearly threw it away on the 18th," added Montgomerie.

For the second day in succession Howell dropped a shot at his final hole of the day. The Swindon golfer had picked up four birdies before pulling his drive on the 18th into heavy rough and eventually missing from six feet for par.

It was still a continuation of the 30-year-old's excellent form this season however, the former Walker Cup star finishing sixth in the NEC Invitational in his second event back after a two-month injury lay-off and then winning his first European Tour title for six years the following week in Munich.

Woods had made a stuttering start with two birdies and two bogeys in his first five holes, but then produced a stunning eagle on the par-four seventh. He had watched as John Daly, in the group behind, drove the green yesterday and insisted he could not hit the ball far enough to do the same.

But with the tee brought forward a few yards Woods was able to smash his tee-shot to within 10 feet of the flag for an eagle two to improve to five under par. A birdie on the 10th was then followed by a bogey on the 13th and birdie on the 14th.

Australian Steve Elkington withdrew before the second round with a back injury.

Elkington carded a three-over 73 in the first round.