Dirk Nowitzki made all 17 of his free-throw attempts, and Michael Finley all 10 of his shots from the line as the Mavericks rallied from two large deficits. They rallied from an 18-point second-quarter deficit, but trailed, 101-87, after Kevin Willis nailed a jump hook with 8:05 left in the final period.
Dallas stormed back, going 20-of-20 from the stripe in the fourth quarter to pull close, then taking its first lead since the first quarter on Finley's hook shot over David Robinson with 14 seconds left.
"In the huddle, coach said he was going to give me a chance to make a play," Finley said. "The big thing in my mind was to just stay aggressive. No matter what I did, I wanted to be aggressive because that's how you make things happen. I knew I had to go strong to the basket and either get fouled or get the basket. Fortunately, I was able to get in the lane and get the hoop."
NBA MVP Tim Duncan, who burned the Mavericks for 40 points, 15 rebounds, and seven assists, tossed an airball over Nowitzki and Raef LaFrentz with six seconds left, and Nowitzki calmly nailed two from the line to make it 113-110 with four seconds to play.
After a timeout, the Spurs elected to keep their best three-point shooter, Bruce Bowen, on the bench because he makes free throws at just 40 percent. In the second quarter, Dallas fouled him repeatedly to send him to the line.
"Nelly (Dallas Coach Don Nelson) has done that before," said San Antonio Coach Gregg Popovich. "We fully expected it, if not tonight, then another time. We didn't take Bruce out of the game (in the first half). I think it was important for his confidence. In the second half, they didn't foul him that way."
The ball was inbounded to Duncan, who was fouled with three seconds to play. Needing to make the first free throw and intentionally miss the second, Duncan missed both. Steve Nash grabbed the rebound and ran out the clock.
Nowitzki had 38 points and 15 rebounds, Finley scored 26 points, and Nash 22 for Dallas, which made its final 49 free throws to go 49-of-50 overall.
"Thank God for free throws," Nelson said. "We're better than anyone in basketball (at that). We're the only team in the league with a free-throw coach, and tonight we needed it. We've taken extra practice the last few days."
"We are normally a good foul-shooting team but struggle at getting to the line," Nowitzki said. "Fifty is astounding, and we did a great job just making plays and getting them into foul shots."
San Antonio missed 17-of-38 free throws.
"What affected us most was missing free throws," Popovich said. "They shot 50 free throws, and it's not like we didn't shoot any, we shot (48). When you shoot 49-of-50 and 31-of-47, you're giving the game away. We know it's a weakness. When you get to the final four teams, those things rear their head."
Tony Parker scored 18 points for the Spurs, who eliminated the three-time defending champion Los Angeles Lakers in the conference semifinals.
Game Two is Wednesday at the SBC Center.