The Boston Celtics rallied from 22 points down to beat the Philadelphia 76ers 114-103 and boost their NBA title credentials at the O2 Arena.

Jaylen Brown scored 21 points with Kyrie Irving adding 20 and Marcus Morris 19 for the Celtics, helping Boston turn a 49-27 deficit midway through the second period into a 69-68 lead by the middle of the third and sending them to a seventh straight win.

JJ Redick led Philadelphia with 22 while Ben Simmons added 16 and Joel Embiid 15.

The eighth regular-season NBA game to be played in London was one of the most hotly-anticipated – with the cheapest tickets going for up to £600 on the day of the game – and this clash of two young teams did not disappoint as a contest.

The 76ers hope they are nearing the end of ‘The Process’ – several years of fielding losing teams which has helped them amass a young core of elite talent, led by Embiid and Simmons – through the draft system.

So far this season it has equated to a middling record, but they arrived in London on the back of four straight wins and the vision was clear to see in a first half when they put Boston in the shade. Simmons played his part, though it was the veteran guard Redick who did the heavy lifting.

The 33-year-old hit a string of three-pointers, scoring 13 points in a first quarter which ended with the 76ers leading 28-23.

It threatened to get ugly for Boston in the second quarter, with the Eastern Conference leaders looking well short of their usual rhythm. They scored only four points in the first 5:44 of the period, dropping into a 49-27 hole as Redick and Simmons paced the 76ers.

But a team that pride themselves on preparation did not panic.

Brown stopped the rot for Boston with a three from the corner, turning to blow a kiss to the Philly bench as he skipped back, and it proved a turning point.

Boston would not get level before the break, but it was the start of a 20-8 run that cut the deficit to 57-48 at half-time.

Boston have key veterans of their own – Irving, who arrived in a summer trade with the Cleveland Cavaliers, and Al Horford – but they are every bit as young as Philadelphia, just ahead in their own process. It was Brown and stand-out rookie Jayson Tatum who did much of the work in the key third period, during which Boston outscored Philadelphia 37-22.

Embiid’s dunk got the crowd off their feet as the buzzer sounded, but it did not count as time expired, and Boston went in to the final period leading 85-79.

They continued to pull clear, with Marcus Smart’s three-pointer bringing up three figures with 7:01 left to play, making it a 69-31 Boston run in 21 minutes of action.

It got testy in the fourth quarter, with Boston’s Morris taking exception to a foul from Simmons to spark a brief melee, but the main battle of the night had already been settled in the Celtics’ favour.

In the other NBA games, the Cleveland Cavaliers lost their seventh game in 10 as they went down 133-99 to the Toronto Raptors.

LeBron James hit 26 points in the loss, which saw the Raptors outscore the Cavs in every quarter.

The LA Clippers saw off the Sacramento Kings 121-115, while Lonzo Ball hit 18 points and 10 rebounds as the LA Lakers beat the San Antonio Spurs 93-81.