Phoenix ? Phoenix apparently will stick with its “double Duncan” strategy in Game 4 against San Antonio tonight, even though it failed in Friday’s 99-86 loss.

However, coach Frank Johnson said his team might be more selective in choosing when to send a second defender at the Spurs’ All-Star, who seemed to bait the Suns into double-teaming him in Game 3.

San Antonio leads the best-of-seven first-round series 2-1. A victory today would send the Spurs home needing just one win to advance.

“If they lose this one, they’re in trouble,” San Antonio’s David Robinson said.

Robinson, who sat out Game 2 because of a partial cartilage tear in his left knee, said he felt fine after his 27 minutes Friday and would be ready today.

Duncan, who took only six shots and scored 11 points in Friday’s victory, feels the series would be virtually over if his team wins Game 4.

“We came here to get two, and that’s the game plan,” he said. “It really is a turning point right now. We could kind of put this series away. Not discounting the fifth game, but we’d really put them in a hole.”

Phoenix could make things more difficult for San Antonio by playing better on the offensive end. The Suns are shooting 39 percent for the series, and managed only 35 percent in Game 3.

Stephon Marbury has been the Suns’ lone consistent offensive threat. In the series, Shawn Marion is shooting 35 percent, Penny Hardaway 35 percent and Joe Johnson, 1-for-11 in Game 3, 25 percent.

San Antonio's Tim Duncan grabs a rebound in front of Amare Stoudemire of Phoenix. The Spurs lead their first-round playoff series 2-1 entering today's game at Phoenix.

“If they shoot the ball halfway decent, where might we be?” Johnson said.

Spurs’ point guard Tony Parker, 3-for-20 in the first two games, scored a career playoff-high 29 points Friday night.

Stephen Jackson added 20 points and is averaging 22 points in the series.

While he didn’t score much, Duncan grabbed 23 rebounds, two short of his career playoff best.

“Honestly, I don’t know if it really matters how many shots I took,” Duncan said. “The guys shooting the ball that well, the guys getting wide-open shots and knocking them down, that just builds everybody’s confidence.”

Johnson said that, in reviewing videotape of the game, he found that the Spurs’ open looks usually weren’t the result of the double-team on Duncan. Instead, they were caused by the Suns’ inability to match up in transition defense.