(My Sportsbook) - Boston may have trumped its disappointing season-opening loss to Chicago with its second setback to the Bulls this season.

Entering Monday's game against Chicago, the Celtics held the top spot in the Atlantic Division by one-half game over New Jersey. The Nets had been rising in the standings, while the Philadelphia 76ers had been fading.

But Boston failed to take advantage of its perch, falling to the Bulls, 94-83, at the United Center.

Paul Pierce was the lone standout for Boston, as he collected 37 points, 15 rebounds and five assists, but the Celtics still had a two-game winning streak halted and fell into a first-place tie with the Nets at 16-8.

Pierce, Antoine Walker (16) and Eric Williams (10) were the only Boston players to score in double figures. The Celtics shot just 33 percent from the field, including 5-of-24 from three-point range, and trailed by as much as 16 in the contest. Pierce hit just 10-of-27 field goal attempts and Walker made only 6-of-18.

"(The) opportunities are there," Pierce said. "We just have to figure out what are the good shots and what are the bad shots. I can't get worried about missing shots. This team needs my shots. I just have to keep playing."

The Celtics missed the shooting of starting point guard Tony Delk, who sat out because of right knee tendinitis. Shammond Williams replaced Delk in the starting lineup, but scored just three points on 1-of-8 shooting.

Walker, who also had nine rebounds against the Bulls, was named Eastern Conference Player of the Week on Monday for games played December 9-15.

Walker averaged 28.8 points on 49.5 percent shooting with 7.8 rebounds, and 5.0 assists as the Celtics went 3-1 last week. He scored a season-high 31 points in a loss to Phoenix on Wednesday before topping that with 33 points in a 115-100 win over Cleveland Friday. Walker also had 11 rebounds and 10 assists against the Cavs for his second triple-double of the season.

Boston captured the honor for the second straight week, as Pierce claimed last week's award.

"With myself getting it this week and Paul getting it last week, it's a good feeling and a good sign," Walker told the Boston Globe. "Hopefully, I can have another good week and can carry it over. We're on TV a lot more and it does a lot for the organization and us as players. It shows we're getting back up to the elite of the league."

The Celtics play home games against Miami and Minnesota before embarking on a four-game road trip that includes a Christmas Day tilt in New Jersey.