The French wonder-striker was made available for the crunch EL encounter shortly after the Gunners successfully appealed to have his ban reduced.
Laca was banned for three matches after being sent off in the first leg of Europa League tie against BATE Borisov last month.
It was, however, reduced to two matches, and the 27-year-old will be back on the pitch to help the Gunners, much to the delight of Arsenal fans:
“Lacazette will save us,” one supporter said.
Another commented: “We should be winning with Laca back.”
A third, meanwhile, made a huge claim for Arsenal’s campaign.
“With Lacazette I can have hopes again in the Europa League,” they said.
And a fourth added: “Rennes will not have a chance.”