Knicks Face a Tough Road Against Celtics : NBA playoffs: Even return of Oakley might not be enough to help New York. Bird is back on his game.

Having gone from first to third in the Atlantic Division in the last 21 games, the New York Knicks might be ready to drop out of sight for good.

When the NBA playoffs open tonight, the Knicks, who spent most of the first part of the season looking as if they were among the class of the league, are at Boston. That only makes matters look more ominous: New York went 9-17 to close the regular season and has lost 24 in a row on the road to the Celtics, a streak that dates to 1984.

The only encouraging news for the Knicks (45-37) is that Charles Oakley, a force inside, has been activated for the playoffs. But even that excitement has to be tempered. X-rays show the broken hand that forced him to miss 18 games has healed, but there is still enough uncertainty about its strength that team officials will leave it up to Oakley to decide about playing.

Boston (52-30) beat the Knicks in four of five games this season. More important for the Celtics, Larry Bird, after a slow start, is playing like Larry Bird. Bird averaged 31.5 points in his last 12 games at Boston Garden and finished at 24.3 overall. The 7.5 assists is also the second-highest of his career.

In close games, you have to like the Celtics even more. They set an NBA record for free-throw accuracy, hitting 83.2%, with Bird leading all individuals and Kevin McHale fifth.

The team with the home-court advantage won 11 of the 15 playoff matchups last season. A look at the other best-of-five first-round series that open tonight, at sites for the first two meetings and Game 5 if needed:

Indiana (42-40) at Detroit (59-23): The Pistons are looking to become only the third franchise to successfully defend a title, following the Boston Celtics and the Minneapolis/Los Angeles Lakers.

After a 14-game improvement from the previous season, Indiana makes its first playoff appearance in three years, with only three players left from that squad. The Pacers’ best chance is familiarity, Coach Dick Versace having spent 2 1/2 seasons as a Detroit assistant.

The Pistons finished with four losses in the last 10 games, but the key factor was Joe Dumars returning to form. They went 3-4 in games Dumars missed because of a broken hand.

Detroit won the season series, 4-1, taking all three meetings at home.

Dallas (47-35) at Portland (59-23): The Trail Blazers, looking to break a streak of not having made it past the first round since 1985, won the season series, 4-0, and the Mavericks weren’t closer than 31 points in the two games in Oregon.

The Trail Blazers used only three different starting lineups all season, with Terry Porter, Clyde Drexler, Kevin Duckworth, Jerome Kersey and Buck Williams opening together in 71 of the 82 games.

Cleveland (42-40) at Philadelphia (53-29): The Cavaliers might have barely reached the playoffs, but this is no easy series for the 76ers.

For one thing, the teams split this season, 2-2. For another, Cleveland opened 18-23 while nursing key players through injuries, but finished 24-17 in the second half after the return of Brad Daugherty. With Larry Nance, Winston Bennett, Daugherty, Mark Price and Craig Ehlo in the starting lineup for 18 of the final 23 games, the Cavaliers went 14-4.

Charles Barkley finished at 60% from the field, second-best in the league, and averaged 25.2 points and 11.5 rebounds. Teammate Derek Smith missed the last four games of the regular season because of tendinitis in his right knee, but he will probably play.

Denver (43-39) at San Antonio (56-26): By winning the Midwest Division title on the last day, the Spurs got the Nuggets instead of having to play the Phoenix Suns.

Get a good look at these Nuggets, for it may be the last time they will be together. In a season of disruptions, in the front office and on the court, management has already indicated sweeping changes could be coming.

San Antonio, which had a 35-game improvement over last season, dared good chemistry by trading Maurice Cheeks to New York for Rod Strickland in midseason. But as long as David Robinson and Terry Cummings are around, the Spurs have a foundation.

San Antonio won three of the four regular-season meetings.