"I played well today", said Cantlay, who was in the clubhouse with a seven-under-par total of 135.
"I bogeyed the two par fives on the back nine, which usually is my bread and butter", McIlroy said.
Long accustomed to eying the top of the leader board to check who is contending with him for a title, Woods could only pay attention to the projected cut line on Friday. He followed that with back-to-back bogeys but grabbed four more birdies to surge up the leaderboard.
Patrick Cantlay (69) and Graeme McDowell (66) shared the lead as the second round was ending. He launched a string of three straight birdies with a near hole-in-one at the par-three sixth, his 15th of the day.
They were one stroke in front of Tom Hoge, Dominic Bozzelli and Sam Saunders on four-under 67, with 11 players tied on 68.
The elite, no-cut event offers a world rankings goldmine and would aid Smith's quest to secure a start a Masters invitation to Augusta. "I'm really excited to be going into the weekend of the tournament on the business end of things".
Woods began his latest comeback with a tie for 23rd at Torrey Pines three weeks ago, a return that brought promise because of the hard conditions and thick rough. Mickelson charges from five shots back, and hangs around the 18th green with McGrady in a last-minute effort to spook Watson.
(Olympics) Canada stunned by Czech Republic in shootout in men's hockey tournament
Maxim Noreau of Canada, reacts after failing to score in the penalty shootout against the Czech Republic. Elsewhere, the Czech Republic edged Canada in a shootout to take control of Group A after two games.
"The feeling of not feeling very good over my putts finally caught up with me", Woods said.
Making matters worse, he wasn't giving himself many comfortable looks.
Despite the problems, Woods said he believed he was progressing in his comeback. "I don't know how to word it another way".
But it's tiring. I need a couple of Advil. His concern over two tournaments has been his iron play, particularly distance control. Earlier Friday afternoon, he committed to next week's Honda Classic, his first time playing back-to-back tournaments since before last year's surgery and first time doing so on the PGA Tour since August 2015. "'Guys, you've got a six-foot putt, it doesn't break as much as you think.' Just stuff like this that they don't have to say".
Woods said he plans to remain at Riviera over the weekend to work on his game. Fifteen players were separated by five shots going into the final round, though the task gets tough with Watson's history. He hadn't teed it up on the classic course west of downtown Los Angeles since 2006 and for his return he played in a marquee group with former world number one Rory McIlroy and reigning PGA Tour Player of the Year Justin Thomas.
What stood out over two days is that Woods can't afford to drop shots the way Thomas and McIlroy can.
Let us leave any pronouncements on his game until he has got a lot more competitive golf under his belt than a mere six rounds.