The 48-year-old American shares the lead at the US$5.8 million (S$8 million) USPGA Arnold Palmer Invitational with compatriot JJ Henry.

Tiger Woods, who is seeking to extend his dynamic win streak, struggled with his irons and managed just two birdies in a modest even-par 70. He is tied for 34th.

'I just didn't feel comfortable with my irons,' said Woods, who has won his past five official tournaments worldwide - four on the PGA Tour and once on the European Tour.

'I missed some greens I don't normally miss - one with a sand wedge, one with a pitching wedge - mistakes I don't normally make.' Woods, who lives nearby, planned a long practice session on the range in the afternoon.

'I couldn't get the ball shaped to start on the right line,' he continued.

'I have some work to do this afternoon. I have a sense of what I needed to do but still need to do the reps and make sure I get nice and comfortable for tomorrow.'

While Woods struggled, Couples turned in a performance reminiscent of the 1990s. He has a one shot lead on Tom Lehman, Vijay Singh, Lee Westwood and Lucas Glover.

'I feel like I can always hit the ball well,' said Couples, the 1992 Masters champion.

Couples won at Bay Hill in 1992, shooting a 63 in one of his rounds.

Back problems restricted Couples to three tournaments last year, and he is playing this year on an exempt status reserved for the top 25 all-time money winners.

Henry made his move around the turn, picking up four birdies in an eight-hole stretch.

'It's been a little bit frustrating, the start of the year,' he said. 'I've worked really hard, felt I've been close and for one reason or another had not quite figured it out.

'Today finally, everything clicked and I hit a lot of fairways and greens, which you have to do on a difficult course like this. Obviously there's a long way to go and I'm really excited the way I hit the ball.' The 49-year-old Lehman, who is seven months older than Couples, also had a solid round.

'I have been working extremely hard on my game and I saw some positive signs and good results today,' Lehman said. -- AFP