OAKLAND, Calif. (AP) — The frustration on Kyrie Irving’s face was evident as he spoke to the media and then buried his head in his hands.

After using the eight-day break to heal his ailing body, Irving looked like his usual self again before limping off the court with yet another injury to his left knee in overtime of the Cleveland Cavaliers’ 108-100 loss to the Golden State Warriors on Thursday night in Game 1 of the NBA Finals.

“It’s disappointing and frustrating because I felt amazing,” Irving said. “This is just a setback that I kind of have to take with a grain of salt.”

The injury happened just minutes after Irving made a defensive play that nearly led the Cavs to the win, blocking Stephen Curry’s layup attempt to give Cleveland the ball with 24.1 seconds left in a tie game.

LeBron James missed a tough fall-away jumper over Andre Iguodala in the closing seconds of regulation. Iman Shumpert grabbed the rebound and threw up a desperation shot at the buzzer that hit the rim and bounced away to force overtime.

“At the end of the day we gave ourselves a chance,” James said. “I missed a tough one. But we had so many opportunities to win this game but we didn’t.”

The Cavaliers missed their last four shots of regulation and first eight of overtime and James had two turnovers as Golden State scored the first 10 points of the extra session. Cleveland didn’t score until James’ layup with 8.9 seconds remaining, shortly before the confetti started falling.

By that point, Irving had already limped to the locker room with a grimace on his face after re-injuring the same knee that forced him to miss two games in the Eastern Conference finals.

“My body works in mysterious ways,” Irving said. “When something gives out, I don’t know exactly what happened. I don’t know. A little different than other times.”

Irving said doctors have ruled out injuries to his ACL and MCL but he still must undergo tests to determine whether he will be able to play in Game 2 on Sunday night.

Irving needed crutches to leave the locker room.

“It was very tough to see,” James said. “I’ve seen how hard he worked these last eight days just to get himself to play at this level tonight.”

Irving had 23 points, seven rebounds, six assists and played some tough defense against Curry. Now, he’s not sure when he will play again.

“Obviously, you can tell by the tone of my voice that I’m a little worried,” he said. “It’s a natural reaction. We’re going to take the necessary steps to see what’s going on.”

Irving was one of the only Cleveland players to support James, who scored 44 points in the highest scoring game of his finals career.

James tied Shaquille O’Neal for the third-most points ever in an opening game of the finals and had the biggest opening game total since Allen Iverson had 48 and O’Neal scored 44 in the 2001 opener.

James’ previous finals high was 37 points against San Antonio two years ago. But in the end, James got too little help.

“He did attack and play and perform at the highest level on the biggest stage in the game, which is appropriate for him,” coach David Blatt said. “We’ve got to do more around him.”

Irving and Timofey Mozgov (16 points) were the only other players in double figures and Cleveland got few other contributions outside of Tristan Thompson’s 15 rebounds.