Already without one All-Star, the 76ers held their collective breath as another left Thursday’s game in the first quarter after landing awkwardly on his right knee.

Yet Joel Embiid’s departure was brief before his dominant return. His teammates couldn’t follow his lead.

Embiid scored 37 points, but the Sixers lost 121-105 to an undermanned Portland Trail Blazers team at the Wells Fargo Center. That snapped a four-game win streak for the Sixers (16-7).

The Blazers (12-9) pulled away with a 40-19 third quarter after the teams were tied 57-57 at halftime.

After blocking a shot from behind by Enes Kanter, Embiid landed awkwardly on his right knee with 5 minutes, 42 seconds left in the first quarter.

Embiid left for the locker room and he was moving gingerly.

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He suffered a hyperextended right knee, but returned to the game with 1:21 left in the first quarter and quickly went to work.

“I was pretty concerned — you never want to mess with any injuries, especially the knee,” Embiid said. “I kind of felt it when I landed but I ended up coming back and pushing through it and as the game went along I felt good. It wasn’t all the way there, but I was just trying to push … I feel good, let’s see how I feel tomorrow when I wake up, but I should be good.”

Embiid was carrying the Sixers, having scored their first 15 points of the second quarter, and going back to the first quarter, he had scored 17 in a row before Tobias Harris hit two free throws with 4:45 left in the half.

He ended with 31 points in the first half and the Sixers needed them all. Embiid was 11-for-17 from the field and he hit all nine of his free throws. He was operating so effectively in the post that Embiid didn’t attempt one first-half three-pointer. He scored 25 of the Sixers’ 29 second-quarter points. That tied the franchise record for points in a quarter set by Andrew Toney, who had 25 on March 21, 1982.

Already the Sixers were without two-time All-Star point guard Ben Simmons, who was out with left calf tightness.

According to coach Doc Rivers, Simmons complained of discomfort after Wednesday’s 118-111 win over the host Charlotte Hornets.

Then again, the Sixers weren’t getting any sympathy from Portland coach Terry Stotts, who was missing six players due to injury, including perennial All-Star guard Damian Lillard and fellow guard CJ McCollum, who combine to average 55.8 points.

Lillard missed his first game of the season with an abdominal strain and McCollum was out for his eighth straight game with a left foot fracture.

Portland only had nine available players.

Rivers started Furkan Korkmaz in place of Simmons. Seth Curry moved from shooting guard to point guard. Korkmaz responded by scoring 10 points in the first quarter.

Neither Korkmaz or his teammates could keep up the energy. Yes it was the second game of a back to back and there was no Simmons, but Sixers were playing a team well more shorthanded than they were.

“That is not an excuse,” Embiid said about the back to backs. ‘We looked tired, including me, we just weren’t focused and they just played better than us.”

» READ MORE: Ben Simmons out of Thursday’s Sixers game with left calf tightness

Curry went scoreless in 12 minutes, 5 second in the first half and didn’t return. The team said he wasn’t feeling well.

This was Curry’s seventh straight game after he missed the previous seven, one with an ankle injury and the other six after testing positive for COVID-19.

Rivers was asked if Curry was still dealing with the after-effects of COVID.

“We’re just checking out everything, that could be part of it,” Rivers said. “He just looks tired and he has looked like that for a while, we just need to be very safe. We are in unchartered waters with all this stuff. He said he didn’t feel great and that is all we needed to hear.”

While Portland couldn’t stop Embiid, the Sixers had trouble keeping Kanter off the boards.

Portland, with Gary Trent Jr. hitting two three-pointers, and Kanter dominating inside, scored the first 14 points of the third quarter before Embiid stopped the bleeding with a 19-foot jumper.

The Sixers were struggling mightily from the perimeter, having missed their first 12 three-pointers before Danny Green hit one with 6:23 left in the third quarter to cut Portland’s lead to 79-66.

Portland continued its third quarter dominance and led 97-76 heading into the fourth quarter.