KSI celebrated wildly in IShowSpeed's face after Martin Odegaard scored against Manchester United.
The Arsenal skipper equalised just seconds after Marcus Rashford had opened the scoring at The Emirates.
And KSI let his emotions get the better of him as he pounded his chest while shouting in Speed's face.
The streamer tried to get his own back on KSI when Alejandro Garnacho struck late on - only for his goal to be ruled out for offside.
Speed had jumped up and down jubilantly and pointed at KSI while laughing excitedly.
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But it was KSI who had the last laugh as Declan Rice scored from a corner minutes later to put the Gunners in front.
Gabriel Jesus then raced through to round off a 3-1 victory for Arsenal, handing KSI the bragging rights over IShowSpeed.
The pair will do battle on the pitch on Saturday for the Sidemen Charity Match at London Stadium.
KSI is set to line-up for a Sidemen side consisting of Miniminter, Zerkaa, Behzinga, TBJZL, Vikkstar123 and WroeToShaw.
While Speed could play with Chunkz, Cal The Dragon and Noah Beck, who all featured last year.
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The match is sold out and is expected to be broadcast live for free on YouTube.
KSI is also preparing for a boxing clash with Tommy Fury on October 14.
Fury headlines the card against KSI with Logan Paul as chief support against Dillon Danis.