Tiger Woods played in the afternoon and went through the front nine with no birdies and two bogeys, dropping him nine shots behind.
Woods, a 14-time Major victor and eight-time champion at the Orlando course, opened and closed the front nine with bogeys but rallied late to shoot a level-par 72 and stand seven shots back on 140 after 36 holes as he works to find consistent top form ahead of next month's US Masters.
Tiger Woods hits his tee shot on the seventh hole during the first round of the Arnold Palmer Invitational golf tournament at Bay Hill Club & Lodge.
Woods made a super 12-foot birdie following a sandwedge on the 18th for a 69.
"Henrik has played great", McIlroy said. His lone comeback also was from five shots behind in 2009, when he rallied to beat Sean O'Hair with a 67 in the final round.
Stenson began the day in a share of the lead and claimed the outright advantage with a 12-foot gain at the first, only for playing partner DeChambeau to drain a 20-footer at the par-three next.
Having started the third round six behind Stenson, his Ryder Cup teammate, the Northern Irishman jumped up to third place at Bay Hill with an eagle, four birdies and just the solitary bogey.
I have been practising these shots, says Karthik
The match took place in the R Premdasa Stadium of Colombo. "Brilliant game, brilliant for the crowd who have come out in numbers". He almost had Tamim Iqbal LBW off the first over he bowled before getting rid of Liton Das caught next over.
After opening rounds of 68 and 72, Woods posted a 3-under 69 in the third round, thanks to six birdies against three bogeys.
Golf needs Tiger Woods and as was very visible last weekend, Tiger Woods needs golf.
BC-GLF-Bay Hill, 1st Ld-Writethru, 853 Stenson takes 1-shot lead at Bay Hill; Woods 5 backAP Photo FLPE119, FLPE133, FLPE118, FLPE124, FLPE120Eds: Updates.
"I've got a chance", he agreed.
"I sort of messed around on the putting green a little bit, trying to go back to some feels I've had before and putted really well".
I've always been a fan of a romantic comeback, and it looks as though our punters think Tiger is onto a Masters victor.
A victory on Sunday could get him back on track, and it would be his first worldwide victory since his incredible performance at the 2016 TOUR Championship. "That was a nice one", the former world number one said of the birdie.
"I know that people want to come and enjoy themselves, and I'm all for that, but it's when the comments get personal and people get a little bit rowdy it can get a little much", McIlroy said. He also made a few mistakes that slowed his momentum and caught some tough lies in the bunkers, but still managed to have his ninth straight round at par or better.