SAN ANTONIO, April 8 (Ticker) -- Tim Duncan had 24 points, eight rebounds and six assists as the San Antonio Spurs built a huge lead over the Portland Trail Blazers and held on for a 99-87 victory, their 11th straight at home.

The Spurs took the lead for good at 6-5 on an alley-oop dunk by David Robinson. They had a 55-39 advantage at halftime and made it 75-46 after former Blazer Steve Smith hit a 3-pointer with 6:20 to go in the third quarter.

"On defense, I thought our whole first-half effort was really good," Robinson said. "That was the key -- we made some great stops and were rotating the shooters. ... We took it to Portland on both ends of the floor there in the second. We really did a good job of get it up and press the issue and were able to make some things happen."

NBA TV highlights from Blazers-Spurs: 56k | 300k Steve Smith helped the Spurs sail past the Blazers. D. Clarke Evans NBAE/Getty Images

But Portland stormed back, getting within 93-87 on a dunk by Ruben Patterson with 2:32 left. Duncan, who had been resting on the bench, returned and hit a turnaround jumper from the right baseline to give the Spurs an eight-point cushion with 88 seconds remaining, and the Blazers did not score again.

"We were a little disappointed with the letdown," Duncan said. "But in the same respect, it's kind of tough being up by that many so early. When that happens, they're going to start firing the threes. If they make them like they did, you've got a game. Otherwise, you end up winning by 50."

The Blazers made six of their first seven 3-pointers in the fourth quarter and 10-of-26 overall.

Smith made three 3-pointers and added 19 points and Robinson finished with 14 for the Spurs, who have won four in a row and 17 of their last 20 games.

"I thought it was a statement game for them, and they played like it," Blazers coach Maurice Cheeks said. "They came out intending to make a statement. They wanted to put their stamp on this one. We made a run and got back in it. It might have got out of hand, but we got back in it. We needed to do something to put some doubt in their mind."

Damon Stoudamire had 23 points to pace Portland, which got only five points on 1-of-13 shooting from Rasheed Wallace. He was guarded by Duncan for much of the game.

"Timmy is one heck of a defender," Spurs coach Gregg Popovich said. "He did a real good (job) keeping himself between Wallace and the bucket."

The Spurs, who have not lost at the Alamodome since February 23 against Minnesota, improved to 3-1 against the Blazers this season.

"We know we can play them well in Portland, but we need to be confident that we can come in here and play them in San Antonio as well," Cheeks said. "We did come back and give ourselves a chance to win in SA tonight, and that's important. You have to be able to win on the road in the playoffs."

San Antonio (53-24) remained a one-half game behind first-place Dallas (53-23) in the Midwest Division and the second seed in the Western Conference playoffs. The Spurs are in fourth place in the West, two positions above the Blazers (46-31).