LOS ANGELES -- The Los Angeles Lakers' postseason run opened with Wednesday's win-and-you're-in play-in game against the Golden State Warriors. And it took everything the defending champions had to win it, 103-100.

LeBron James' 34-foot 3-point heave to beat the shot clock buzzer fell through the net with 58.2 seconds remaining, breaking a tie at 100 and giving L.A. the lead for good.

James, playing on a right ankle that caused him to miss 26 of the Lakers' final 30 games down the stretch while recovering from a sprain, finished with 22 points, 11 rebounds and 10 assists for the first play-in triple-double in the tournament's two-year existence.

With the win, the Lakers claimed the No. 7 seed in the Western Conference playoffs and will face the Phoenix Suns in the first round. L.A. opened as a -300 favorite to win the series, according to Caesars Sportsbook by William Hill. It's the first time in at least the past 30 years that a 7-seed is favored over a 2-seed, according to ESPN Stats & Information research.

The Warriors will play the Memphis Grizzlies for the eighth seed Friday. Memphis defeated San Antonio in Wednesday's other play-in game.

James' clutch 3 was his longest make of the season. According to ESPN Stats & Info, it was also the longest go-ahead shot in the final three minutes of any game in his career.

About a minute before hitting the shot, James was shaken up when he drove to the basket and took a hard foul to the face from Draymond Green.

"After Draymond's finger to the eye, I was literally seeing three rims out there," James said. "So I just shot at the middle one. And I was able to, with the grace from the man above, I was able to knock it down."

Warriors coach Steve Kerr gave credit to James for delivering in the clutch, but also praised his team's effort.

"He made a great shot obviously at the end," Kerr said. "We've played against him so many times over the years, we know how good LeBron is, what he's capable of. He came through for them.

"I just love our guys' effort the whole game. Draymond was amazing tonight guarding [Anthony] Davis, and I thought [Andrew Wiggins] did a great job on LeBron. Our guys really, really just battled and competed. I couldn't be more proud of the team for what they've become over the last couple of months."

The Warriors, led by Stephen Curry's 37 points, couldn't get their star one last shot to try to tie it, as Kent Bazemore turned it over, throwing an errant inbounds pass with 2.1 seconds left that bounced feebly down the court as time expired.

The game mirrored the Lakers' struggles for much of the second half of the season, as L.A. initially struggled to find a rhythm before storming back at the end.

An Anthony Davis alley-oop dunk on the first play of the fourth quarter tied the score at 79-79 -- the first time L.A. knotted the score since the opening tip -- and the Lakers opened up the floodgates from there.

Kyle Kuzma scored on a hook shot from 8 feet out to give the Lakers their first lead of the night, and James, guarded by second-year guard Juan Toscano-Anderson, went to work.

James scored on isolation drives on consecutive possessions, giving the Lakers an 85-79 lead with 9 minutes, 50 seconds to go in the fourth.

The Warriors, pushed by the league's leading scorer, Curry, did not go quietly into the night.

Golden State mounted a comeback of its own, erasing L.A.'s lead -- which swelled to as many as seven -- to take the lead back, 96-95, on a Jordan Poole 3-pointer with three minutes, 43 seconds remaining.

Curry drove and hit a floater off the glass the next trip down, putting the Warriors up by three on the next possession.

Things couldn't have gone much worse for the Lakers in the first half, with James shooting 1-for-7, Dennis Schroder shooting 1-for-9 and Davis going 2-for-12.

Still, the Lakers' defense, ranked No. 1 in the regular season, kept the Warriors from breaking the game open. Even with Curry beating the halftime buzzer with a 3-pointer in front of his team's bench -- sending his teammates into a euphoric tizzy -- Golden State's lead was 13 heading into the locker room.

Andre Drummond, L.A.'s big in-season acquisition after being signed from the buy-out market, looked out of place, registering more fouls (three) than points (two) in the first half.

Lakers coach Frank Vogel stayed with his starting lineup -- Drummond included -- to begin the third quarter and the big man's presence started to pay off. His defensive rebound and look-ahead pass to James early on in the third led to an and-1 layup for the Lakers' star, prompting Golden State to call timeout just one minute, 28 seconds into the third with L.A. cutting the lead to just six.

A Schroder 3 a couple of minutes later brought L.A. within one, at 57-56, but the Warriors -- with James on the bench to rest -- responded with a 15-4 run of their own to balloon their lead back to 12.

L.A. responded again, however, and trailed by just two headed into the fourth quarter.