P.J. Washington Jr. made two free throws before an intentional miss with 2.5 seconds left, lifting the Dallas Mavericks to a 117-116 victory over the Oklahoma City Thunder on Saturday night and into the Western Conference finals for the second time in three seasons.Washington was fouled by Shai Gilgeous-Alexander on a 3-point attempt after Chet Holmgren had put the Thunder in front 116-115 with a dunk on an assist from his star guard with 20 seconds remaining.Luka Doncic, who had 29 points, 10 rebounds and 10 assists, worked his way to the basket in the final seconds before passing to Washington in the corner. Washington pump-faked to get Gilgeous-Alexander in the air and the whistle blew as the shot fell short.Oklahoma City challenged the ball, but replay showed Gilgeous-Alexander making contact with Washington’s arm as he went up to shoot. After making the first two free throws to put Dallas in front, Washington missed on purpose, and Holmgren passed to Jalen Williams, whose desperation shot from well behind half court wasn’t close.The Mavericks wrapped up the series in Game 6 at home against the top-seeded Thunder, just as they did in the first round against the Los Angeles Clippers. Dallas trailed by 17 points in the third quarter. The final sequence capped a riveting fourth quarter with five lead changes and two ties in the final five minutes after the Thunder led for all but one minute until then.Gilgeous-Alexander scored 36 points, his most in the playoffs this season, while Jalen Williams had 22 points, nine rebounds and eight assists and Holmgren scored 21.Kyrie Irving and Derrick Jones Jr. scored 22 points apiece for Dallas. It was the second consecutive game with a playoff career high for Jones.