Content provided by Associated Press. Picks by Covers.com staff.
Dallas Mavericks at San Antonio Spurs (-5, 189.5) 
Tim Duncan has never lost a first-round playoff series, and only once since the Spurs won their first championship in 1999 has San Antonio not advanced in the postseason. But down 3-1 to the Dallas Mavericks, the third-seeded Spurs must win at home Tuesday night in Game 5 or their season is done.
"We haven't been in that position very often,'' Spurs coach Gregg Popovich said Monday. "It is what it is. You just play the games and deal with it.''
It was a typical, non-alarmist Popovich response. But it's been anything but a typical postseason for the Spurs, who are saddled with trying to become just the ninth team in NBA history to storm back from a 3-1 deficit and win a series.
Unmoved by the daunting task facing San Antonio are the Mavericks, who want to seal their first playoff series victory in three years and not be lulled into a Game 6 back in Dallas.
The Mavs have been here before: Up 3-1 against the Spurs in the 2006 conference semifinals, San Antonio rallied to even the series and forced Dallas to wrest the series in overtime of Game 7.
"I've never lost in the first round,'' Spurs guard Tony Parker said. "It's just a different situation. Right now, Dallas is just playing better than us. We've been down 3-1 before, and we came back and gave us a chance in Game 7. So that's the motivation right now, to take care of Game 5.''
Role players, always essential to San Antonio, have fizzled this series. Duncan and Parker combined for 75 percent of San Antonio's points in a 99-90 loss in Game 4, and it still wasn't enough. The duo made 25 of 42 from the field, and everyone else had 6 of 28.
It appeared to underscore how much the Spurs are missing Manu Ginobili, who is out for the playoffs with a stress fracture in his ankle. The Mavericks have taken notice, too, that his absence alone makes this hardly the same Spurs who stormed through the playoffs in previous seasons.
Pick: Mavs
Houston Rockets at Portland Trail Blazers (-5.5, 182)
Youth and inexperience are catching up with the Portland Trail Blazers.
The youngest team in the postseason has struggled with Houston's Yao Ming to fall behind 3-1 in the playoff series with the Rockets and faces elimination Tuesday night in Portland.
Yao had 21 points and 12 rebounds in an 89-88 victory over the Blazers on Sunday night. Once his teammates were able to get him the ball inside, Yao was nearly unstoppable. When Portland tried to double him, that left someone else open.
While focused on Yao, the Blazers also made some crucial mistakes that cost them after leading 70-64 going into the fourth quarter.
Two obvious errors came with less than a minute to play. First, when a falling Joel Przybilla badly overthrew Steve Blake after rebounding Blake's missed 3-point attempt, the ball sailed into the backcourt. Then, with Houston leading 87-85, Portland's Brandon Roy drove to the basket and was called for an offensive foul when he ran into Chuck Hayes.
The victory moves Houston closer to advancing to the second round of the playoffs for the first time since 1997.
Portland has had trouble matching up with Yao the whole series. In Game 1, the Blazers had Przybilla play behind the 7-foot-6 center from China - which didn't work.
Portland seemed to find more success when Przybilla fronted him. A rarely used combination of Przybilla and rookie Greg Oden - both 7-footers - playing at the same time also tricked the Rockets in Game 2, Portland's lone win thus far.
Home court could help Portland on Tuesday. The Blazers were 34-7 at the Rose Garden during the regular season.
Two-time All-Star Roy, a third-year player with no playoff experience, has the job of rallying his team for Game 5.
"I don't want anybody in our locker room to get down,'' said Roy, who had 31 points in Game 4 and is averaging 28.3 in the series. "I think this is a great experience. We're fighting extremely hard. There's just some minor things we have to improve on. And just going through this experience I think will help us in the long run.''
Roy did not practice Monday afternoon because of flu-like symptoms, but he was listed as probable for Tuesday's game. A call to the Blazers to provide more details about his symptoms was not immediately returned.
LaMarcus Aldridge, who was averaging 16.5 points and 8.3 rebounds for Portland during the playoffs, also didn't practice Monday because of a right elbow strain. He was also expected to play in Game 5.
Pick: Rockets