The clock high above the FleetCenter ice reads 2:21 remaining in a 2-1 game on the first Monday in February. Over on the Boston University bench, Head Coach Jack Parker, playing with the lead in the semifinals of the 51st annual Beanpot Tournament, urges his penalty-killing line on the ice and Mark Mullen, out of St. Margaret's Parish, vaults the boards and heads up ice. Mullen snares the puck near the red line and executes a neat backhand dump into the Harvard zone.

Harvard calls for a timeout a few seconds later and Mullen is pulled, but back on his skates with under a minute left, as the Terriers guard their one-goal lead in a bid to reach their 19th Beanpot final in the last 20 years. Mullen wins a face-off, flicking the puck to the Harvard end of the rink to kill another 10 seconds and when BU goaltender Sean Fields mitts a glove save with nine seconds to go, the game is all but ended. Mullen clinches it, poking the puck down ice and chasing it as time expires.

After the game, Parker will dub his junior star, "no question, the best defensive forward in this league."

Mullen seems surprised when told of Parker's compliment, saying, "You do whatever you can to help the team, but I do take pride in playing good, solid defensive hockey."

He's more excited, though, with the win than with any individual honors. Politely and delicately balancing a hot dog in his right hand while fielding a few queries from reporters, he's got his eye on the most coveted trophy in New England hockey.

"We really just don't want to play in any consolation games," Mullen says. "That's a goal of ours in every tournament we play."

And Mullen's come to the right place, one of the most prestigious college hockey programs in the nation, an NHL factory that brings home Beanpot hardware home with a regularity that leaves fans from Harvard, Northeastern, and Boston College shaking their heads in frustration. The most recent came just one year ago, when Mullen was just one of seven Terriers to appear in every game of the season.

This year, he's an even more valuable part of the team, one of the Terrier's premiere penalty killers. Parker says he relies on Mullen for face-offs and for duty in both the left wing and center spots.

The 21-year-old Dorchester native, from Roseclair Street, started playing hockey with his older brother and played in South Boston leagues for the proximity. Top youth hockey players don't invest in their games part time, so Mullen spent a lot of times in rinks growing up. When he got to Boston College High School, practice and academics hogged his time.

"He was playing hockey so much, he didn't have time to go to a lot of social events," says Mullen's father, Brian. "He spent a lot of time playing hockey and he was pretty good while he was young, so he really worked at it."

Mullen's mother, Kathleen, has run a daycare center out of their home for 20 years, Brian says, so Mullen had plenty of potential teammates growing up. Now that Mullen has become one of the country's top icemen, the little kids borrow his old equipment and follow in his skatemarks.

"All the little kids really look up to him," his father says, adding that some of them have gone on to become excellent players in their own right.

Few of them, though, will reach the level attained by Mullen, who has notched seven goals and 11 assists for the Terriers this year, leads his team with two shorthanded goals, and is tied for third with 18 total points.

Besides that, he's an emotional leader on the squad.

"Mark's really stepped up, on and off the ice," says BU captain and star defenseman Freddy Miller. "Mark's a great kid, a guy who always come to play. He's always diving, blocking shots, doing whatever it takes to win. I really love the way he plays."

Mullen is modest when asked about his success, shushing any talk of an NHL career. Enrolled in BU's School of Hospitality Administration, he says he's thought about coaching, too, helping out with a BU hockey camp when he can.

"I love helping little kids play hockey," Mullen says. "Being around kids is just fun for me."

If he strays from pucks and sticks, he says, "I've turned into a little boy again, I guess, and since September 11th, I've though about becoming a firefighter."

Still, playing professionally is a dream of any college athlete, albeit a little more feasible one for a player of Mullen's caliber.

"It's been a dream of mine since I was a kid and, obviously, that would be the ultimate goal."

For now, though, there's one more Beanpot game to win, Monday night against BC. And for someone who grew up in the city, there are few bigger games.

"I don't think there's any question that it means more to these guys, because they know they're going to be around here for the rest of their life," Parker says of Bostonians.

Mullen says, "I think it means a little more just because I've grown up with it and I've seen it my whole life and know what a great tradition it is."

Next Monday, with the FleetCenter clock ticking away the seconds, Mullen will be hoping that tradition is on his side.