Al Horford: Celtics lacked defensive urgency against Embiid-less 76ers.

Boston -- Despite MVP candidate Joel Embiid being sidelined with a damaged right knee, the Boston Celtics lost Game 1 in Boston 119-115 to the Philadelphia 76ers in the Eastern.

Conference playoffs on Monday night. Boston shot 58.7% and got 39 points from Jayson Tatum.

But Philadelphia shot 50.6%. James Harden's 45 points and go-ahead 3-pointer with 8.1 seconds left powered the Sixers.

I felt like we started off well offensively, but I don't think there was a sense of urgency on the defensive end," Celtics center.

Al Horford said after the game.Embiid's absence tonight was a factor, even if you deny it. Be better. We must be able to play with any variable. Our staff.

Has done it for whatever reason." Tatum didn't think the Celtics misjudged the Sixers without Embiid, but he did think Boston's.

Defense wasn't good enough. "We let guys get too comfortable," Tatum said. "We can improve. Offensive rebounds cost us.

Second- and third-chance opportunities. It's about increasing pressure and making people uncomfortable... everyone is gifted and feels a little more free out there.