Joel Embiid felt like he was destined to struggle from the outset in the Philadelphia 76ers' 114-103 defeat to the Boston Celtics in London on Thursday.

The Sixers entered the match on the back of four straight wins but let a 22-point second-quarter lead slip to fall to a third loss against the Celtics this season.

Embiid shot just four-of-16 from the floor and missed all six of his three-point attempts in his previous outing against Boston in October. The center endured similar difficulties this time around - he was six-of-17 for 15 points at the O2 Arena.

"I started off really frustrated by the way everything was set up and from there if I'm not having fun, or another way for me to have fun is to kick someone's a*** or talk trash, then usually I have a bad game," Embiid, who still posted a double-double with 10 rebounds, told a media conference.

"I was just not in the rhythm. I didn't do a good job of letting my team-mates find me either, so I don't think they [the Celtics] did anything special.

"I feel like it was the way the offense was set up. I feel like in the third quarter we didn't move the ball. We kept going back down and trying to find the mismatch.

"I don't think it was the rhythm, I just wasn't finding my spots. Like I said, I was frustrated from the beginning and usually if I'm frustrated I have bad games."

Jaylen Brown led the Celtics in scoring with 21 points and praised Al Horford, Aron Baynes and Daniel Theis for shutting the Sixers big man down.

Brown said: "I give credit to our guys, Al and Baynes, Theis, they come out and execute the gameplan. Just trying to make him uncomfortable.

"It's hard to guard him by yourself so our team mindset is to make it hard for him, to get tough looks."

A seventh straight win keeps Boston sitting pretty at the top of the Eastern Conference at 34-10.

The Celtics defeated the Minnesota Timberwolves at the O2 Arena in the preseason of their title-winning 2007-08 campaign, but star point guard Kyrie Irving – who contributed 20 points, seven assists and six rebounds against the Sixers – feels the reshuffled group must first discover their identity before considering a championship bid.

"We have to be dialled in at every moment. It's a long season still ahead and we're a little bit past the halfway point – it's great for that to happen for that past team but it's the past and we have to be very present," said Irving, part of the Cleveland Cavaliers side that claimed the title in 2016.

"Winning an NBA championship is one of the hardest things you can do in your life. As a young, developing group we still have to take advantage of the opportunities afforded to us to grow and really figure out who we want to be and our identity on a consistent basis.

"Once we do that we'll feel like we've put ourselves in a great position to deal with the things thrown at us in the future. We're still in the regular season, we have the playoffs to play, and until we get to that point where we'll be tested, mentally and physically… those are still steps we need to take."