MEMPHIS, Tenn. – Forget slowing down in the playoffs, the Phoenix Suns sprinted right into the Western Conference semifinals.

Joe Johnson scored 25 points, and the Suns swept the Memphis Grizzlies with a 123-115 victory last night that put Phoenix into the second round for the first time since 2000. They now get to rest and wait to see if they will play Dallas or Houston.

It’s the first sweep by the Suns in a best-of-seven series and their first since the 1995 playoffs when they took Portland 3-0 in a best-of-five opening round.

Steve Nash added 24 points and nine assists for the Suns, who outshot Memphis in the highest-scoring game of these playoffs 60.3% (38-of-63) to 50.6% (45-of-89). Shawn Marion contributed 23 points and 11 rebounds, Jim Jackson had 19 points, Amare Stoudemire added 18, and Quentin Richardson had 14.

The Suns out rebounded Memphis 37-28 and had more trips to the free throw line (49) than Memphis made shots from the floor (45).

Pau Gasol scored a playoff-best 28 points to lead the Grizzlies, who extended their NBA record to eight straight playoff losses. They will have to wait until next season to try for the young franchise’s first postseason victory.

With empty seats scattered around the arena, it seemed the biggest question would be when the rest of the fans would start leaving as the Suns ran up and down the court and built a 19-point lead by the end of the first quarter.

The Suns had more fast break points in the quarter (16) than they’d had in either of the last two games.

The Grizzlies kept trying to slow down Phoenix by grabbing, pushing, and pulling at every chance. The Suns shrugged off even the most flagrant foul when Dahntay Jones put his arm into Marion on a drive to the basket in the fourth quarter. Marion went down hard, but the ball went in for a 100-89 lead.

In the end, Memphis, a team that held Phoenix to just 95.5 points in four games in the regular season, couldn’t do enough against the NBA’s top-scoring team.

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PISTONS 97, 76ERS 92

When it was time for Detroit to get back into the game or allow Philadelphia to even their playoff series, Chauncey Billups took over. Billups made two clutch 3-pointers. He hit a nice fadeaway, and sank a couple of foul shots.

By the time Billups finished scoring 10 straight points for the Pistons in the final 3:05 of regulation, the 76ers’ lead was gone – and so might have been their shot at making this a long series.

Billups scored 12 of his 25 points in the fourth quarter, Rasheed Wallace hit a couple of 3-pointers in overtime, and Detroit overcame an inspired effort by Allen Iverson to go up 3-1 in its first round series with a 97-92 win over the Sixers yesterday.

The Pistons survived another scare from Philadelphia, and headed home with a chance to wrap up their playoff series. Game 5 is Tuesday in Detroit.

After Billups carried the Pistons in a frantic finish to the fourth quarter, Wallace hit a decisive 3-pointer with 1:29 left in OT. Richard Hamilton hit a runner on the baseline with 14.5 seconds left, then sealed the win with a couple of free throws. Wallace’s 3-pointer came right after Chris Webber hit a 3-pointer and Iverson made two free throws, tying the game at 90.

Rasheed Wallace had 17 points and Ben Wallace added 12 points and 12 rebounds for the Pistons, who bounced back from a Game 3 loss Friday night.

Iverson again did his best to carry the Sixers, scoring 36 points on 14-for-24 shooting with eight assists. Webber added 23 points, including several key second-half buckets. Samuel Dalembert had 15 rebounds.