Philadelphia 76ers head coach Doc Rivers issued a warning about Joel Embiid's health despite his injury return, insisting "we're still not out of the woods" as the Eastern Conference top seeds look to bounce back against the Atlanta Hawks.

Embiid returned from a meniscus tear in Philadelphia's shock 128-124 loss at home to the fifth-seeded Atlanta Hawks in the NBA Eastern Conference semi-final opener on Sunday.

MVP finalist Embiid sat out the series-clinching win over the Washington Wizards due to the right knee injury, which he sustained in Game 4 of the opening-round matchup.

The 76ers outscored the Wizards by 31.6 points per 100 possessions with Embiid on the court but were outscored by 7.5 points per 100 possessions when he went to the bench (excluding Game 5), according to Stats Perform.

Embiid led all scorers with 39 points on 12-for-21 shooting, while he also had nine rebounds, four assists, three blocks and a steal against the visiting Hawks in Philadelphia.

Gearing up for Tuesday's Game 2 at Wells Fargo Center, Rivers provided an update on All-Star Embiid following Monday's practice, telling reporters: "He looked pretty good.

"Obviously, we didn't do much today, but just my observation, without being a real medical doctor, is that he looked pretty good. We were happy with everything."

Embiid has been averaging 27.0 points, 7.2 rebounds and 2.8 assists per game in this season's playoffs, while he boasts career highs in field-goal percentage (61.6), three-point percentage (43.8) and free-throw percentage (90.5).

In 2020-21, Embiid has averaged a career-high 28.5 points, 10.6 rebounds and 2.8 assists per game.

"I think we always have to worry," Rivers added. "I don't think we're out of the woods, I'll put it that way. I think after each game he's gonna be evaluated for a while.

"I don't know how long that lasts, there may be three or four or five games, but we're still not out of the woods, I guess, would be the best way to describe it."

The 76ers were blown away by Trae Young and the Hawks, who led 75-54 at half-time. According to Stats Perform, that is the highest first-half point total by a road team in a postseason series opener in history.

Young had 25 of his 35 points in the first half as the Hawks outscored the 76ers 42-27 in the first period.

Philadelphia's Ben Simmons (17 points and 10 assists) had a double-double but it was a disappointing outing for the 76ers, who are eyeing their first championship since 1983.

However, All-Star Simmons remains upbeat, adding: "The confidence has always been there. I think it's just more so we got to lock in and be ready for whoever comes in the building because it's not going to be easy.

"It's the playoffs and this is a good team we're facing right now. They play the right way. They share the ball, and they play together. We got to come together and play the right way."