Big Papi is big fan of Horford.

Byline: Jennifer Toland

BOSTON - Hanging in the locker of Atlanta rookie Al Horford last night was a Boston jersey - a Red Sox jersey to be precise.

The grey top with red No. 34 was signed, "To my boy Al Horford, go and get them. David Ortiz."

Horford and Ortiz, both natives of the Dominican Republic, had lunch together yesterday.

Horford, who moved to the United States when he was 15 and helped the University of Florida to back-to-back national championships, has followed the Red Sox since the late 1990s. His mother, Arelis Reynoso, is a good friend of former Sox ace Pedro Martinez, also a Dominican.

"That's how I got following the Red Sox," said Horford, who grew up in Santo Domingo, "and I became a big David Ortiz fan. Even when Pedro left, I kept on following them."

Over at Fenway Park last night, Ortiz homered and fellow countryman Manny Ramirez scored the winning run in the ninth as the Red Sox beat the Blue Jays, 2-1. Horford was not able to work the same magic at the Garden.

With 14 points and 10 rebounds, Horford posted his third double-double of the opening-round Eastern Conference series, but the Celtics won, 110-85, to take a 3-2 series lead.

Game 6 is tomorrow night in Atlanta.

"Early in the game, we didn't get stops like we needed," Horford said, "we didn't rebound the ball. They got to a lot of loose balls and things like that and that was the difference. It's important for us to set the momentum early."

The Hawks cut into the Celtics' 15-point halftime lead with a run in the third quarter, but the C's built the lead back up to 17 heading to the fourth.

Horford said he and Ortiz "heard about each other," but met for the first time just last week. Ortiz was in attendance for Game 1 at the Garden. They had lunch together at Ortiz's home the next day.

"David Ortiz is big in the Dominican," Hawks forward Josh Smith said, "and Al Horford is becoming that way, too."

Horford, who averaged 10.1 points and 9.7 rebounds during his first pro season, learned yesterday he finished second to Sonics guard Kevin Durant in the NBA Rookie of the Year voting. Durant, who averaged 20.3 points, will be named winner of the award today.

Horford sent Durant a congratulatory text message yesterday.

"It was a deserved award," Horford said. "He's been consistent all year. I'm happy for him. We're still real cool."

Durant led all rookies in scoring, assists and free-throw percentage, but Seattle failed to make the postseason.

Horford, the third overall pick in last year's draft, helped lead Atlanta to the playoffs for the first time in nine years.

"As a team, we have an opportunity to do something big," Horford said. "That's what I'm focusing on."

The Hawks face a must-win situation in Game 6. If a Game 7 is necessary, it will be here Sunday.

"We still got a life," said Hawks guard Joe Johnson, who scored 21 points. "It ain't over yet. We have to go home and take care of business."

Horford is averaging 12.8 points, 11.2 rebounds and 3.6 assists in the series.

In Game 1, when he scored 20 points and pulled down 10 rebounds, he became the 24th rookie in NBA history to put up at least 20 points and 10 boards in his playoff debut. He was also the first Hawks player to do it.

Horford, whose father Tito played three years in the NBA, had 17 points, 14 rebounds and 6 assists in Game 3, a 102-93 win in Atlanta, but he made even more news for getting in Paul Pierce's face and triggering the Celtics captain's now infamous "menacing gesture," for which he was fined $25,000.

Earlier in Game 3, after Smith blocked a Rajon Rondo shot, Horford took the ball and pretended to dust it off. Horford said it was "an in-the-moment type thing."

Last night, Horford was assessed a flagrant foul late in the first half after taking Kevin Garnett down as he drove to the basket.

NAME: BOSTON CELTICS; BOSTON RED SOX