And so the Celtics remain a contradiction.

One of the oldest, creakiest teams in the NBA seems to get better the longer the game lasts.

Paul Pierce wore his 50 minutes like a weight after the Celtics got off the floor just in time to dodge the broom with yesterday’s 97-90 overtime win over the New York Knicks in Game 4 of the Eastern Conference quarterfinals.

The Celtics, 7-4 in overtime during the regular season, made the extra time work for themselves again yesterday after first blowing a 20-point lead.

Jason Terry, the 35-year-old guard who has been off-kilter all season and played 41 minutes yesterday, scored the Celtics’ last nine points during overtime, including the game’s last six points overall. The only golden-ager to avoid the minutes crush was Kevin Garnett, who packed 13 points, six assists and his second straight 17-rebound performance into 37 minutes.

But with elimination the alternative, it was yet again time for the oldest to carry the burden.

“There was a lot of pride,” said Pierce, who had 29 points, eight rebounds, six assists, five fouls and yet another ghastly turnover count (this time six). “For us, the captains of the team, we gotta install in these guys the attitude. You saw before the game we were going to come out with the force we did today and then carry it over to the game.”

The Celtics ultimately were able to put their best quarter of the series — a 32-point second — on the board for a 54-35 halftime lead. One Jeff Green 3-pointer into the third quarter, that lead became 59-39.