'I played well all day,' said Love, who set a new 54-hole tournament record. 'It's nice to be excited and playing aggressively and feeling good.'
Love was one shot off the lead when the second round was completed early Saturday morning and the 38-year-old had a slow start to his third round on the Sunset Course at the Country Club at Mirasol. Love parred his first seven holes until a birdie at the eighth.
At the par-5 ninth, Love hit a remarkable second shot to seven feet for an eagle to make the turn at 16-under. He continued his fine play on the back nine and hit his approach to six feet for a birdie at the 10th.
After a weather delay of just over two hours, Love returned to the course and landed his second shot inside 14 feet for birdie at the 12th to stand alone atop the leaderboard at minus-18.
Love was soon overtaken by Leonard, who closed his round with six consecutive birdies to enter the clubhouse at 19-under. Love persisted and tied Leonard with a two-putt birdie at the par-5 15th.
The 1997 PGA champion regained the outright lead with a birdie at the par-5 17th. Love, who won the Pebble Beach National Pro-Am in February, parred the 18th to secure a one-shot advantage with one round to play.
'Winning is very important, but feeling good and being in there is what I want to do all year long,' said Love. 'If somebody behind us tomorrow shoots 59 or 60, there might not be anything we can do about it, but I'm going to go out there and try to birdie every hole tomorrow with a good attitude.'
Players have gone low all week, and Love was cautious in his outlook for Sunday's final round.
'It's a good day to keep your head down, not look at the scoreboards and just play,' said Love. 'There really isn't much of a lead here.'
Leonard opened with a bogey at the third that dropped him back to 10-under but he recovered with a pair of birdies starting at the fourth hole. Leonard then birdied the eighth to make the turn at minus-13.
The 30-year-old holed a 40-footer for birdie at the 13th and birdied the 14th before play was called with a storm moving through the area. Leonard was not affected by the delay and picked up where he left off with a birdie at the 15th.
'It's just fun,' said Leonard. 'Especially to do it with a weather delay in between, having to go back out and warm up again. Just to be able to do it like that, to get back in contention, because I felt like I was falling out of contention, feels pretty good.'
At the par-3 16th, Leonard knocked his tee shot within two feet for his fourth consecutive birdie. He continued the run with a birdie at the 17th and hit his second shot to 16 feet at the 18th. Leonard drained the putt for his sixth straight birdie and a round of 64.
'It gets a little boring out there when the scores are so low and you're making a bunch of pars,' said Leonard. 'You feel like you are treading water and it can get a little frustrating. But I think being able to go out and make six birdies in a row, and knowing that that's possible, somehow keeps me in it.'
Chris Riley chipped in for birdie at the par-4 18th to finish alone in third at 18-under-par 198.
Billy Mayfair, Woody Austin, Carlos Franco, Jerry Kelly, Tom Byrum and Notah Begay III, who held a share of the lead after round two, were one shot further back at 17-under-par 199.
Brett Quigley, Chad Campbell, Mark O'Meara, Shaun Micheel and 2002 Q-School medalist Jeff Brehaut finished tied for 10th at 16-under-par 200.
David Peoples, who finished alongside Begay in a tie for the lead after the second round, was quiet Saturday with a round of 71. Peoples finished five shots off the lead in a group at 15-under-par 201.