TORONTO — Kyle Lowry scored 30 points, but it wasn't enough to lift the undermanned Toronto Raptors over the San Antonio Spurs on Tuesday.

LaMarcus Aldridge had 21 points, while Patty Mills had 18 and the Spurs (36-9) edged Toronto 108-106, to hand the Raptors (28-17) their fourth consecutive loss.

The Raptors hadn't lost four straight since March 4-10 of 2015.

Terrence Ross scored 13 of his 21 points in the fourth quarter for the Raptors, who were playing without DeMar DeRozan. Norman Powell added 16 points, Patrick Patterson finished with 12, and Cory Joseph finished with 10.

DeRozan, who leads the team with 27.9 points a night, is out at least two games with a sprained right ankle after landing on the foot of Jonas Valanciunas in the fourth quarter of Sunday's 115-103 loss to visiting Phoenix.

DeRozan will also miss Wednesday's game in Memphis, then be re-evaluated later in the week.

Raptors coach Dwane Casey's motto is "next man up," and on Tuesday, Ross, Patterson, Joseph, and Lucas Nogueira on the defensive end, stepped up big-time to take the No. 2 team in the Western Conference to the wire.

Patterson's return was welcome. He played just his third appearance in the last 13 games because of a sore knee.

The Spurs were missing Kawhi Leonard (hand injury), who'd scored 30-plus points in six consecutive games.

The Raptors trailed the Spurs all night, finally taking their first lead midway through the third quarter. The game went into the fourth all tied up at 79-79, to the delight of a capacity Air Canada Centre crowd of 19,800 fans.

Ross opened the fourth quarter with a pair of three-pointers and when he drilled a three with 4:23 to play, the basket put Toronto up 102-98. With the Raptors trailing by a point, Ross threw up a three that circled the rim tantalizingly before dropping out with 11.3 seconds to play. Aldridge was fouled on the play, and his free throws made it a three-point game before a Powell dunk with 6.2 left pulled the Raptors to within a point once again.

An Aldridge free throw clinched San Antonio's victory.

Toronto had lost 18 of the last 23 meetings against San Antonio, including a 110-82 decision in Texas on Jan. 3.

The Raptors couldn't buy a basket in a first quarter that saw them miss 12 of their first 15 shots. The Spurs took an eight-point advantage but baskets from Powell and Joseph cut San Antonio's lead to 29-25 going into the second.

Toronto pulled to within a point early in the second, but the Spurs used a 15-4 run to go up by 13, and took a 61-54 lead into the halftime break.

Joseph led the way with eight points in the third, and his driving layup tied the game 70-70 with three minutes left in the third. A Ross free throw gave the Raptors their first lead late in the quarter.