Porter Powers Trail Blazers, 122-112 : Western Conference: His 27 points and seven assists help Portland take a two-games-to-none playoff lead over San Antonio. Drexler adds 22 points.

Terry Porter and Clyde Drexler keyed a 24-8 third-quarter outburst as the Portland Trail Blazers beat the San Antonio Spurs, 122-112, Tuesday night to take a two-games-to-none lead in their Western Conference semifinal series.

Porter finished with 27 points and seven assists, and Drexler had 22 points as the Trail Blazers won their fifth consecutive playoff game.

“The momentum was just pumping,” Drexler said of the third-quarter run. “The crowd got into it and things were clicking.

“It all started on the defensive end,” he said. “We got the ball into the open court and we were getting layups, getting fouls and taking the ball to the basket strong.”

Terry Cummings scored 33 for San Antonio, and David Robinson added 31. But 17 of Robinson’s points came after Portland built a 20-point lead with 1:41 left in the third quarter.

The best-of-seven series shifts to San Antonio for Game 3 Thursday night.

An 11-4 run to end the second quarter gave Portland a 63-55 halftime lead, then the Trail Blazers took control of the game in the third quarter.

Led by the tenacious defense of Porter and Drexler and the shot blocking of Wayne Cooper, Portland outscored the Spurs, 24-8, to start the quarter, opening an 87-63 lead with 4:25 left in the period.

Cooper had four blocked shots in the quarter, including one against a dunk attempt by Robinson. Drexler scored 11 points and had two steals, and Porter scored nine and had three steals in the quarter.

Robinson led a Spurs’ comeback that narrowed the margin to 105-96 on Cummings’ 16-footer with seven minutes to play. But Porter made a 20-footer and Jerome Kersey sank two free throws to boost the lead to 13.

Portland was 43 for 51 from the free-throw line to set a team playoff record for free throws made and attempted. The Trail Blazers were 29 for 45 from the line in their 107-94 victory over the Spurs Saturday.