PHILADELPHIA -- After James Harden had the two worst consecutive shooting games of his entire career in Games 2 and 3 of the Philadelphia 76ers' Eastern Conference semifinal series against the Boston Celtics, coach Doc Rivers decided to remind his star guard of who he is heading into Game 4.

"I sent him a gospel song," Rivers would later say with a laugh. "The title of it is, 'You Know My Name?'

"I'm on my way to the game, and I get a text from Doc," Harden later explained with a laugh. "It's a gospel song, and I'm like, 'All right, whatever.' So, I just tell my homies, 'Let's play the song.' It's a 7-minute song, but I let the whole song play.

"I was like, 'All right, there's got to be some kind of good ju-ju in this song, or however he's feeling, I want to feel like that.'

"And I guess it worked."

It certainly did. Harden not only finished with a spectacular line -- 42 points on 16-for-23 shooting, including 6-for-9 from 3-point range, to go along with eight rebounds, nine assists, four steals, a block and just one turnover in 47 minutes -- but he hit the game-tying shot in the closing seconds of regulation before burying a corner 3-pointer with 19 seconds to go to lift Philadelphia to a stunning 116-115 overtime victory on Sunday.

This titanic Eastern Conference showdown now heads back to Boston knotted at two games apiece -- and does so because Harden rediscovered the magic he had in Game 1, when he poured in 45 points to lead Philadelphia to a win without Joel Embiid. Then, in Games 2 and 3, he combined to shoot 5-for-28 from the field -- the worst two-game shooting performance of his career, according to ESPN Stats & Information research.

There were no such issues Sunday.

"That's what he needs to do every night," said Embiid, who finished with 34 points, 14 rebounds and four assists in 46 minutes in just his third game back from a sprained LCL in his right knee. "Not think about anything.

"It's not about taking a lot of shots. It's just about being aggressive, attacking the rim, finding guys, and he was fantastic tonight."

Philadelphia needed him to be, as Embiid, in particular, appeared to run out of gas in the game's closing minutes. He got his shot blocked by longtime nemesis Al Horford three times in the final few minutes of the fourth quarter -- prompting P.J. Tucker to give the newly-minted MVP a fiery pep talk on the court as a way to try to pump him up, with Embiid later admitting he didn't play well.

"I'm on my way to the game, and I get a text from Doc. It's a gospel song, and I'm like, 'All right, whatever.' So, I just tell my homies, 'Let's play the song.' It's a 7-minute song, but I let the whole song play. I was like, 'All right, there's got to be some kind of good ju-ju in this song, or however he's feeling, I want to feel like that.' And I guess it worked."

James Harden

"Nobody can guard Joel one on one," Tucker said. "There's no way. I'm sorry. It's no disrespect to Al or anybody else. But I've guarded him for a lot of years and when he's aggressive and assertive, it's impossible. And I seen him two, three plays in a row not do that. And we can't have it. We can't have it. Not with the season on the line. We can't have it."

Fortunately for the 76ers, they had Harden turning back the clock to his own MVP days for the second time in a week. After Harden buried a runner to tie the game with 15 seconds to go in regulation, only for Marcus Smart to miss a potential game-winning 3 at the buzzer, Harden's go-ahead 3 in overtime came off a terrifically-designed out of timeout play by Rivers that got Embiid matched up with Jayson Tatum inside, causing Jaylen Brown to react with a double-team that left Harden wide-open in the corner

"Just a bad read," Brown said of his decision to double-team Embiid down low, leaving Harden open for the game-winning shot. "That's it. A gamble at the wrong time. Big shot by James Harden, but that's my fault. I take full accountability. Just a bad read."

Sunday's game winner, coupled with his game-winning 3 in the waning seconds of Game 1 last Monday, are two of Harden's three go-ahead field goals in his career with less than 30 seconds to go in a playoff game.

According to ESPN Stats & Information research, he'd entered this series 1-for-10 in those moments. He's now 2-for-2 in this series.

"I just want to win," Harden said. "No matter how it plays out, I just want to win.

"Quite frankly, today was a do-or-die for us ... we found a way to win, and that's all that matters in the postseason."

And while Harden was correct about the stakes at play in the series had Philadelphia lost -- particularly with Boston heading back home for Game 5 Tuesday night, as well as a potential Game 7 -- it certainly looked like things were headed in that direction when, after the 76ers had led by as many as 16, Boston took a 5-point lead when Malcolm Brogdon buried a 3-pointer with just over two minutes remaining in the fourth quarter.

But the 76ers found a way to survive.

"Our goal is to go to Boston and win," said Embiid. "I'll be better. We just got to go out and find a win and come back here up 3-2."