LeBron James scored 31 points as the Los Angeles Lakers won a thrilling duel with the Phoenix Suns 106-103 on Tuesday to advance to the semi-finals of the NBA's in-season tournament.

James produced a trademark clutch fourth quarter performance with 15 points in a victory that sends the Lakers into a last-four showdown with the New Orleans Pelicans in Las Vegas on Thursday.

In Tuesday's other quarter-final, Giannis Antetokounmpo and Damian Lillard combined for 63 points as the Milwaukee Bucks advanced to the semi-finals with a 146-122 rout of the New York Knicks.

But the game of the night was unquestionably in Los Angeles, where James and the Lakers held off a ferocious second-half fightback from Kevin Durant and the Suns to prevail in a classic.

The Lakers dominated the first half to lead by 12 at the break, up 59-47.

But the Suns roared back in the third quarter, outscoring the Lakers 35-24 to make it a one-point game heading into the fourth.

The 38-year-old James though was in no mood to surrender victory and found his scoring touch to shepherd the Lakers over the line.

Austin Reaves nailed a superb three-pointer to give the Lakers a four-point advantage with 15 seconds on the clock.

Durant cut the gap to two points with a reverse layup but missed with a last-gasp attempted buzzer beater that would have forced overtime.

"I've been there a lot in my career and I understand the assignment," James said of his ruthless fourth-quarter display.

"I was happy I was able to make a couple of plays, but the big shot came from AR (Austin Reaves) to take us up by four... that was big-time."

James finished with 31 points from 12-of-25 shooting, with 11 assists and five rebounds. Anthony Davis added 27 points with 15 rebounds while Reaves added 20 points in a scintillating cameo from the bench.

Durant led the Phoenix scoring with 31 points while Grayson Allen and Devin Booker finished with 21 points apiece for the Suns.