Tiger Woods completed one of sport's great all-time comebacks to end an 11-year major title drought at the Masters on Sunday by claiming a fifth Green Jacket.
The 79-year-old Nicklaus holds the record for most major golf championships with 18, with Woods now trailing the mark by three.
National Basketball Association stars LeBron James and Steph Curry also expressed their admiration, although Curry hoped for a little more from Woods as a result of him claiming a fifth green jacket.
"Even when guys were shooting 64 on Saturday, I was just kind of going around, just handling my business, work your way up the board and make sure that I keep myself in the event".
Dressed in his traditional final-round red shirt, Woods collected his first birdie of the day, rolling in an eight-footer at the third, to trim Molinari's lead to a single shot, but then gave it right back with a bogey at the par-three fourth. When I tapped in I don't know what I did, I know I screamed.
A USA gambler was probably as excited as Tiger Woods over his victory at the Masters.
"My dad was here in 1997 and now I'm the dad with two kids here", he added. Overnight leader Francesco Molinari title charge collapsed with two double bogeys.
Paired together in the final round of last year's British Open, won by the Italian at Carnoustie, Molinari and Woods found themselves in the last group again battling for a major title.
They will tee off at 9:20 am ET (1320 GMT) as officials pushed up start times in a desperate bid to get the season's first major across the finish line before storms hit.
Lurking one shot further back is two-times defending U.S. Open champion Brooks Koepka, who will head off in the company of Webb Simpson and Englishman Ian Poulter, both four off the pace. But on Sunday it was Molinari who slipped up, with the 36-year-old from Turin finding the water at the 12th and 15th. I am so happy for him and for the game of golf.