By Tim Reynolds

AP Basketball Writer

LAKE BUENA VISTA, Fla. (AP) — Jayson Tatum scored 34 points, Marcus Smart made five 3-pointers in the fourth quarter and the Boston Celtics beat the Toronto Raptors 102-99 in Game 2 of their Eastern Conference semifinal series Monday night, putting the reigning NBA champions in serious trouble.

Smart scored 19 points, Kemba Walker had 17 and Jaylen Brown scored 16 for the Celtics, who now hold a 2-0 series lead. The Celtics are 3-0 against Toronto in the NBA’s restart bubble at Walt Disney World, and 5-1 against the Raptors this season.

OG Anunoby had 20 points for Toronto, which got 19 from Fred VanVleet — who missed a 28-footer as time expired. Serge Ibaka and Pascal Siakam scored 17 points apiece and Kyle Lowry added 16 for Toronto.

Smart made three 3-pointers on three consecutive possessions in a 73-second span early in the fourth, then added another 3 about a minute later — and a four-point play a minute after that, putting Boston up 86-85 with 7:55 left.

It was part of a 29-9 run by Boston, with the Celtics going up 95-87 with 4:18 left.

The Raptors finally seemed they had matters figured out late in the third quarter, taking a 12-point lead — the momentum seeming like it had swung on an overturned call that, correctly, went Toronto’s way. A layup by VanVleet, followed by a free throw from Siakam after officials reversed a call that he said he fouled Smart, gave Toronto a 78-66 lead with 2:46 left in the third.

The Raptors scored only nine points in the next 10:39. But just when things looked like they had gone totally awry, Toronto scored five straight to make it a 95-92 game with 3:35 left, and the Raptors got within one on a pair of free throws by Lowry with 1:01 remaining.

But Walker hit a stepback on the next Boston possession, and the Celtics held on from there.

TIP-INS

Celtics: Boston has won six straight playoff games, its first such streak since 2017. The franchise record is seven straight, set on the way to the 1986 NBA title. … Robert Williams was 5 for 5 in the first half, notable because he had never taken five shots in any first-half appearance of his career. He’s had two 5-for-5 halves in the bubble; his other was in the second half against Brooklyn on Aug. 5.

Raptors: Siakam, who was disrupted in Game 1 by three early fouls, didn’t get his first until 7:56 remained in the third quarter. … After not leading at any moment in their first two meetings with Boston in the bubble, the Raptors needed only 47 seconds before getting out front in Game 2. … Lowry now has three or more steals in 10 games this season, including playoffs — the 10th straight year he’s had at least that many.

FIRST-HALF ANOMALIES

There were a pair of unexpected shooting notes from the first half: Toronto didn’t take a free throw and Walker went 0 for 8 from the field. It was the first time Toronto never got to the line in the opening two quarters of any game since a playoff matchup with Cleveland on May 23, 2016. And Walker tied for the worst-shooting first half of his career; he also was 0 for 8 in the opening half for Charlotte in a loss to Golden State on Dec. 2, 2015.

GOT SMART

Smart became the second player in these playoffs with five 3-pointers in a fourth quarter. Denver’s Jamal Murray did it twice in the first six games of the Nuggets’ series against Utah.

UP NEXT

Game 3 is Thursday.