The Boston Celtics got off to the best 29-game start in NBA history, but knew that historic run would be tested with their first significant road trip of the season.

So far, it couldn't be going any worse.

Losers of back-to-back games after winning 19 in a row, the Celtics will try to get back in the win column Sunday night when they visit the struggling Sacramento Kings.

Boston (27-4) had been off to an even better start than last season's championship-winning team, running off 27 wins in its first 29 games. The Celtics looked like a serious threat to top the 72 wins of the 1995-96 Chicago Bulls for the most in league history.

For all the accomplishments of the NBA's most history-laden franchise, Boston had never won 19 games in a row until Tuesday. The Celtics crushed Philadelphia 110-91, their final home game before heading to the West Coast for the first time this season and their first road trip of longer than three games.

In their first meeting with the Los Angeles Lakers since Boston's six-game win in the NBA finals, the Celtics lost 92-83 on Christmas Day at Staples Center, but it was a loss up the California coast the next day that was alarming.

Boston led Golden State 51-39 at halftime on Friday night, but fell apart in the second half, getting outscored 35-17 in the fourth quarter of a 99-89 loss to the Warriors.

"I was worried at halftime when I saw we were shooting 56 (percent) and they were shooting 39 and it was a 12-point game," coach Doc Rivers said. "Once they start making shots, it's tough to turn them off, and we couldn't make anything."

The Celtics had 23 turnovers on Friday - 14 in the second half - and point guard Rajon Rondo had seven. Rondo had six combined turnovers in his previous four games.

Boston hasn't lost three in a row since Feb. 19-22, its first three contests after last season's All-Star break.

"I think we're all looking at ourselves in the mirror individually to see what we can do to get better, to make this team better," said Celtics reserve Eddie House, who is 4-of-15 from the field in the last two games.

Ray Allen also has had problems on this road trip, which ends Tuesday in Portland. He went 5-for-14 from the floor - 3-of-11 on 3-point attempts - for 14 points versus the Lakers and was held to a season-low seven points Friday while battling foul trouble.

Boston is 20-1 when Allen scores at least 15 points.

Allen scored a game-high 17 in the Celtics' last trip to Arco Arena, an 89-69 win on Dec. 26, 2007. Boston had lost its previous 11 games in Sacramento.

These Kings (7-23), though, have won just twice in their last 17 games. Sacramento was swept on a four-game road trip - all against opponents with winning records - before blowing a halftime lead in a 107-101 home defeat to Toronto on Friday for its fifth straight loss.

"A lot of times we really don't even know what we are doing," said center Brad Miller, who tied a season high with 20 points. "So we just have to keep working on it and look at it and keep going at it."

Miller and the Kings allow 43.5 points per game in the paint, and Boston (43.7) averages more than anyone in the East. The Celtics should get an added boost inside with the expected return of starting center Kendrick Perkins, who sat out Friday's game with a sore left shoulder.

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