April 21 (Bloomberg) -- The Boston Celtics and Los Angeles Lakers opened their National Basketball Association playoff series with wins, while the Philadelphia 76ers upset a Detroit team with the league's second-best record.

The Celtics, the No. 1 seed in the Eastern Conference, routed Atlanta 104-81 in Boston yesterday, while the Lakers, the top team in the West, defeated Denver 128-114 behind a 36-point, 16-rebound effort by Pau Gasol.

The Pistons, whose 59-23 regular-season record was second only to the Celtics, blew a 15-point second-half lead in losing at home to the 76ers 90-86. Also yesterday, Orlando beat Toronto 114-100 to open their first-round series.

In today's NBA playoff games, Cleveland hosts Washington up 1-0 and Utah welcomes Houston with a 1-0 series lead. The home teams have won seven of the first eight games in the postseason.

All NBA playoff series are best-of-seven.

AT TD Banknorth Garden in Boston, Ray Allen scored 18 points, Paul Pierce had 16 and Kevin Garnett added 16 points and 10 rebounds for the Celtics.

``It's a good win,'' Pierce, who was taken out of the game in the closing minutes before the Celtics' lead swelled as high as 27 points. ``We'll take it for what it's worth and we don't think it was our best basketball game.''

NBA's Best Record

Boston is favored by oddsmakers to win its first NBA title in 22 years after going a league-best 66-16 during the regular season. The Celtics are now 4-0 this season against the Hawks, who made the playoffs with a 37-45 record, and will host Game 2 in two days.

``In the regular season you can have your ups and downs. In the playoffs you can't have your downs,'' Pierce said at a post- game news conference. ``But we're here and we're ready to go.''

In Los Angeles, Gasol made his playoff debut with the Lakers a winning one after going 0-12 in three previous postseason trips with Memphis. The Lakers acquired the 7-foot center from the Grizzlies in February.

Gasol helped Los Angeles outscore Denver 39-22 in the third quarter at the Staples Center to break open a two-point game, while Kobe Bryant scored 18 of his 32 points in the fourth quarter to keep the Lakers in control.

``I knew he could perform at a high level,'' Bryant said of Gasol at a news conference. ``This isn't Memphis. This offense has freed him up a bit and showcased more of what he can do instead of just being in the post all the time.''

Lamar Odom added 17 points and 14 rebounds for the Lakers, who will host Game 2 of the series in two days. Carmelo Anthony and Allen Iverson each scored 30 points for the Nuggets.

76ers Upset Pistons

At the Palace of Auburn Hills in Michigan, the 76ers outscored the Pistons 43-24 in the final 18 minutes.

Andre Miller scored 20 points to lead Philadelphia, which made the playoffs with a 40-42 record and is seeded seventh in the Eastern Conference.

Willie Green added 17 points for the 76ers and Andre Igoudala had 16 points, 9 rebounds and 8 assists.

Rasheed Wallace had 24 points, 9 rebounds and 7 blocked shots to lead the second-seeded Pistons, who host Game 2 of the series on April 23.

``We've got to fire back on Wednesday,'' Pistons coach Flip Saunders said at a news conference. ``It's a must-win game now.''

In Orlando, Florida, Dwight Howard had 25 points, 22 rebounds and 5 blocked shots as the Magic opened a 24-point first-half lead and held on for their first playoff win since the 2002-03 season.

Anthony Parker paced Toronto, the sixth seed in the East, with 24 points and added 7 rebounds.

Jameer Nelson scored 24 points and Hedo Turkoglu had 21 for third-seeded Orlando, which hosts Game 2 tomorrow.

To contact the reporter on this story: Erik Matuszewski in New York at matuszewski@bloomberg.netMason Levinson in New York at mlevinson@bloomberg.net.

Last Updated: April 21, 2008 01:03 EDT