SAN ANTONIO, March 14 (Ticker) -- The San Antonio Spurs extended the NBA's longest winning streak, but surprisingly, it wasn't easy.

Tim Duncan scored 24 points and grabbed 14 rebounds and David Robinson added 15 and 17 as the Spurs held off the stubborn Chicago Bulls for their eighth straight victory, 91-86.

The Spurs, 1 1/2 games behind the third-place Los Angeles Lakers in the Western Conference, needed a 10-0 run midway through the final quarter to go ahead for good.

"We made far too many mistakes, but we're always happy with a win," Duncan said.

NBA TV highlights from Bulls-Spurs: 56k | 300k Trenton Hassell helped give the Spurs a mighty scare before fouling out. D. Clarke Evans NBAE/Getty Images

Chicago refused to quit, closing within 88-86 on Jalen Rose's 3-pointer with 17 seconds left before Antonio Daniels made three free throws to seal the win.

"We played hard and really competed. I thought we did a good job and gave ourselves a chance to win this game," Chicago coach Bill Cartwright said. "I was really proud of our guys; everybody who played, played well."

"Tonight was one of those ones we had to just fight out," Robinson said. "They wouldn't go away, they kept coming back at us."

Guard Steve Smith, the Spurs' second-leading scorer, left after being fouled hard going for a layup midway through the second quarter. After X-rays of his right ankle proved inconclusive, an MRI was scheduled for Friday morning.

Marcus Fizer collected 22 points and 12 rebounds and Travis Best chipped in 22 points for the last-place Bulls, who have lost eight in a row overall and six straight on the road.

Daniels and Tony Parker each scored 12 points for the Spurs, who escaped with the victory despite making just 30-of-45 free throws and shooting 40 percent (28-of-72) from the field.

"The shooting 45 free throws is ridiculous," Cartwright said. "I don't know what we are going to do about that."

"I've been around the league a long time," Bulls forward Charles Oakley added. "I try to play hard on defense and when you do that you're going to get fouls called on you."

Duncan carried the Spurs at the charity stripe, going 12-of-13, but Robinson was 7-of-11 and Daniels just 4-of-9.

Rose netted 20 points, nine rebounds and six assists as the Bulls outworked San Antonio on the boards, 52-49, but were just 15-of-22 from the line.

Trailing 65-57 midway through the third quarter, Chicago surged ahead with a 14-3 burst that was capped by Fizer's bucket 71 seconds into the fourth for a 71-68 advantage.

The Spurs regained the lead when Parker's free throw with 4:50 to play finished a 10-0 run. Bruce Bowen and Danny Ferry both had three points in the burst.

"We're not going to be able to play like we played tonight (against Boston on Saturday)," Duncan said. "A win tonight was good for the streak, but we will have to raise our focus for this upcoming stretch."

San Antontio, which has yet to lose in March, led 46-42 at halftime.