On a night when an unstoppable LeBron James poured in 51 points for the Cleveland Cavaliers in Game 1 of the NBA Finals, the Golden State Warriors need some help in securing a victory.

They got it, in part, through a costly blunder by Cleveland’s J.R. Smith and a disputed foul call involving James -- en route to a 124-114 win in Oakland, Calif., on Thursday night.

Stephen Curry scored 29 points and the Warriors capitalized on Smith's mistake -- which sent the game into overtime.

Just prior to OT, James jawed with both Curry and Klay Thompson, then Tristan Thompson and Draymond Green tangled moments later and made contact. After replay review, Tristan Thompson received a Flagrant 2 foul and ejection with 2.6 seconds left.

James was in utter disbelief as regulation ended stunningly: George Hill made the first of two free throws with 4.7 seconds left after being fouled by Klay Thompson, but when Smith secured the rebound of the second, he dribbled back toward half-court instead of shooting, apparently thinking the Cavs had a lead.

"He thought it was over. He thought we were up one," coach Tyronn Lue said.

"He thought it was over. He thought we were up one." — Cavs coach Tyronn Lue

Yet Smith insisted he knew the score. Green figured Smith was simply looking for James, saying, "I would have looked for LeBron, too."

"I just thought we were going to call a timeout. Because I got the rebound, I'm pretty sure I couldn't shoot it over KD," Smith said of Kevin Durant. "If I thought we were ahead, I would have just held on to the ball so they could foul me. Clearly that wasn't the case."

"I just thought we were going to call a timeout. Because I got the rebound, I'm pretty sure I couldn't shoot it over KD." — Cleveland's J.R. Smith

Instead, OT. And why not? Both these teams were pushed to their limits in seven-game conference finals they each had to win on the road.

"I can't talk about a situation that way because I do some dumb stuff on the court," Durant said of how the fourth quarter finished. "I don't know what was going through J.R.'s head. He made a great rebound and gave them an opportunity to win the basketball game."

"I don't know what was going through J.R.'s head. He made a great rebound and gave them an opportunity to win the basketball game." — Golden State's Kevin Durant

Game 2 is Sunday night back at Oracle Arena, where the Warriors have won 18 of their last 19 postseason games.

James shot 19 for 32 to go with eight assists and eight rebounds in the opener of his eighth straight NBA Finals and ninth overall, as well as Cavs-Warriors Take IV. James notched his eighth 40-point game during this playoff run to tie Hall of Famer Jerry West's feat in 1965 for most in a single postseason.

The Associated Press contributed to this story.