SPOKANE, Wash. (AP) — No. 4 Gonzaga beat undermanned Portland by 21 points on Saturday, but the Zags were not happy.

Portland, playing without its leading scorer, out-rebounded the Zags 41-33, and held Gonzaga, the nation's last remaining undefeated Division I team, to 45 percent shooting.

"We have to start rebounding better," said center Przemek Karnowski, who scored 12 points but had just three rebounds in Gonzaga's 73-52 victory. "Five guys have to go and rebound the ball. That's one of the things we need to fix."

Nigel Williams-Goss led Gonzaga with 15 points, but left the game with about five minutes left with an injury. Coach Mark Few could not say exactly what the injury was or how serious.

But he was also unhappy with the rebounding.

"They pounded us for 21 offensive rebounds," Few said. "They beat us to some balls."

"It was a choppy game," Few said. "Portland did a nice job. They played us physical."

Zach Collins added nine points and nine rebounds for Gonzaga (19-0, 7-0 West Coast), which has a nation's best 19-game winning streak. It is the best start in program history.

Gabe Taylor scored 13 points and Jazz Johnson 12 for Portland (9-10, 2-5), which has lost five games in a row. The Pilots played without leading scorer Alec Wintering, who earlier Saturday was declared out for the season with a torn ACL.

"Sometimes when you lose your leader like that, it wipes you out," Portland coach Terry Porter said. "But the guys responded well with a great effort."

"We knew it was going to be a tall task," Porter said. "I loved the way we fought and got after it."

Gonzaga, which has won seven straight over Portland, never trailed despite shooting 45 percent from the field. Portland was worse, shooting just 32 percent.

"We had a lot of good looks we didn't knock down," Few said.

Gonzaga opened the game with a 12-1 run and the Pilots did not make their first field goal until five minutes were gone. The Zags hit four 3-pointers in the first 10 minutes and built a 24-11 lead. They were up 34-23 after a sloppy first half in which neither team shot better than 40 percent.

Early in the second, Gabe Taylor hit three consecutive baskets for Portland to knock Gonzaga's lead down to 38-31.

But Killian Tillie's 3-pointer ignited a 15-3 run that put Gonzaga in control and the Pilots did not threaten again.

BIG PICTURE

Portland: Under first year coach Terry Porter, the Pilots started strong but have been suffering offensive woes in recent weeks. The problem may get worse as Wintering, who was averaging 19.5 points per game, suffered a torn ACL in Thursday's loss at San Francisco and is done for his college career.

Gonzaga: The Bulldogs have dominated at home this season, outscoring opponents by 29 points per game in their first 10 contests in the McCarthey Athletic Center. They have trailed a total of 13 minutes in their first 11 home games.

QUOTABLE

"They fought us and did a good job of competing with us," Few said.

TURNOVERS

The Pilots turned the ball over 16 times, to 10 for Gonzaga.

UP NEXT

The two teams will play again on Monday in Portland, in a make-up date for a Jan. 7 game that was postponed by severe winter weather. Saturday's game started a run of four games in eight days for each team. "We're trying to get guys rested a little bit," Few said.

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