Bobby Portis scored a season-high 28 points against his former team, including a go-ahead 3-pointer with 1:47 remaining, and the New York Knicks beat the Chicago Bulls 105-98 on Monday night for their first victory of the season.

Portis hadn't scored in double digits yet in his first season with the Knicks, but was superb in bringing New York back from an 18-point deficit. The reserve was 10 for 14, making all four 3-pointers, and added 11 rebounds.

The Knicks needed all of it on a night when they fell behind with a dreadful start and stayed that way until the fourth quarter. They never even led until Portis' go-ahead 3, which he followed with another 3 that pushed it to 103-98 during a 15-0 run to finish the game.

Portis was a 2015 first-round pick of the Bulls. He spent 3 1/2 seasons in Chicago before being traded last season to Washington. He signed with the Knicks over the summer.

Rookie RJ Barrett added 19 points and 15 rebounds for the Knicks, who had dropped their first three games. Kevin Knox II scored 14 points, and Julius Randle finished with 13 points, 14 rebounds and five assists.

Zach LaVine scored 21 points for the Bulls, who fell to 1-3. Wendell Carter Jr. had 20 points and 10 rebounds.

The Knicks missed 13 of their first 15 shots and quickly fell behind by double digits. The Bulls led 33-15 after one quarter and re-opened an 18-point cushion in the third quarter.

The Bulls visit Cleveland on Wednesday.