At the age of 47, Mickelson is the oldest winner of any World Golf Championship event and will fancy his chances of winning a fourth Masters title next month, with a US Open victory to complete a career grand slam also looking a more realistic prospect.

Woods turned 42 in December and will play the fourth PGA Tour event of his latest comeback when he makes his debut in the Valspar Championship this week, where he has been paired with Spieth and Henrik Stenson in the first two rounds at Innisbrook.

"Seeing Phil win I think was really cool for Tiger, to recognise I've got all this time to be still able to get to that high level," Spieth told a pre-tournament press conference.

"Knowing his nature that he's displayed over the last 20 years, it still wouldn't be surprising if, come Masters time, he's in the hunt on Sunday and that's pretty amazing to say."

Spieth also believes Mickelson and Woods now have more in common, adding: "There's a lot of similarities now. Tiger's a family man, he's been more open with everybody compared to what I heard he was like before, which was head down, focus, this is go time and I'm here to kick everyone's ass.

"Now he's got his friends out here, he recognises where he's at in the process that's coming forward for him."

Woods underwent spinal fusion surgery in April 2017, his fourth back operation in the space of three years, but has looked pain-free in his competitive appearances in 2018.

The 14-time major winner finished 23rd in the Farmers Insurance Open, missed the cut in the Genesis Open and was 12th in the Honda Classic before committing to the Valspar Championship and next week's Arnold Palmer Invitational.

Asked if he is inspired more by the younger generation winning tournaments or the likes of Mickelson, Woods added: "It's both. To watch the young guys do what they're doing is what they're supposed to do - this is their generation.

"What Phil's doing is showing us we can still do it later on in our careers. Davis (Love) did it at 51 I believe, Phil at 47, Kenny Perry won a handful of events post-45 so there are a few guys that can do it late in their career. For me, I'm ecstatic just to have a chance to play again and have a chance to win golf tournaments.

"There was a while there where I didn't look like I was ever going to be out here again. I think I've come around very quickly, I've only played 10 rounds.

I know people are saying I've been a little erratic, a little inconsistent but it's 10 rounds. I looked up some of my stats last night and I'm not even on the rankings - I haven't played enough rounds."

Woods has missed the Masters through injury in three of the last four years and confirmed he will make an early visit to Augusta National to get reacquainted with the site of four of his major victories.

"There's definitely going to be some of the younger guys up there with a chance who are playing really well at the time, but Augusta is also one of those courses that favours the vets," Woods added.

PA