NEW YORK — Kristaps Porzingis made a tiebreaking 3-pointer with 40 seconds left in overtime after Jayson Tatum’s 3-pointer with 2.9 seconds remaining forced the extra period, and the Boston Celtics completed a season sweep of the New York Knicks with a 119-117 victory Tuesday night.

Porzingis matched his season high with 34 points on his 30-footer. Tatum added 32 points as the Celtics extended their road winning streak to eight and improved to 33-7 away from Boston.

They had routed the Knicks by 23, 27 and 13 in the three previous meetings, but needed to fight beyond 48 minutes for this one.

Karl-Anthony Towns had 34 points and 14 rebounds for the Knicks. Jalen Brunson added 27 points and nine assists in a strong second game back after a 15-game absence because of a sprained right ankle.

Takeaways

Celtics: Boston became locked into the No. 2 seed in the Eastern Conference during the game when Cleveland completed its victory over Chicago. But the Celtics’ road success won’t leave them with any concerns about a potential conference finals matchup without home-court advantage.

Knicks: Maybe New York got some confidence against Boston after not leading by more than one point in any of the first three matchups. But this loss probably hurt more than any of those.

Key moment

The Knicks took a three-point lead on Josh Hart’s basket with 11 seconds remaining in regulation but chose not to foul the Celtics, who have more 3-pointers this season than any team in NBA history. Tatum then made his to even it up at 107.

Key stat

The Celtics are 20-4 since the All-Star break.

Up next

The Knicks visit Detroit on Thursday in a possible playoff preview. The Celtics are at Orlando on Wednesday.