The England Under-21 international joined Arsenal trio Calum Chambers, Olivier Giroud and Alex Oxlade-Chamberlain at The O2 on Thursday night.
The Premier League stars appeared to enjoy watching the Toronto Raptors ease to a 106-103 victory over the Orlando Magic in the English capital.
Arsenal missed the chance to cement their lead at the top of the Premier League table following a 3-3 draw with Liverpool at Anfield on Wednesday.
Slaven Bilic’s impressive West Ham side edged closer to fourth-placed Tottenham Hotspur after a 2-1 win against Bournemouth in the Premier League on Tuesday night.
Jenkinson, Chambers, Oxladde-Chamberlain and Giroud will become rival again on 9 April when Arsenal make the trip to Upton Park.
West Ham were memorable 2-0 winners against Arsene Wenger’s side on the opening weekend of the Premier League season.
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