Premier League - Arsenal throw away two goal lead
The hosts looked comfortable after Robin Van Persie opened the scoring on 29 minutes before half-time substitute Aaron Ramsey doubled their advantage with his first touch two minutes after the break.
Lucas Viatri halved the deficit after 69 minutes before Arsenal’s old failings rang true once again when Djourou allowed Mouche in to level.
Arsene Wenger handed debuts to new boys Gervinho and Carl Jenkinson for the visit of 23-time Argentine champions Boca, who lost 3-1 to Spanish side Espanyol on Wednesday in the first game of their European tour.
The 19-year-old Jenkinson only made his debut for Charlton Athletic in December 2010 and went on to make a handful of appearances for the Addicks before being snapped up by Arsenal in June, while Ivory Coast international Gervinho signed from Lille in July.
And Gervinho made an immediate impact, beating his man after eight minutes before sending in a low cross which Van Persie hit wide on the turn.
And it would be the 24-year-old Gervinho set-up Arsenal’s opener, surging forward on the left before whipping in a teasing ball which Van Persie turned home at the near post.
Wenger made five substitutions at half-time and Ramsey was soon on the score sheet, sending a rasping shot past the Boca keeper from the edge of the box after a darting run by fellow sub Vela.
That looked to have sewn the points up but Sebastien Squillaci carelessly gave away possession in his own half and Viatri went on to lash home from 18 yards.
Boca had done little to justify their reputation as South America’s most decorated team until then but that breathed renewed confidence into Julio Casar Falcioni’s side.
And the visitors pounced when Djourou got the wrong side Mouche to allow the Argentina international to slot home and leave Wenger pondering his side’s defensive misgivings just two weeks before the Premier League campaign begins.