The 24-year-old Brazilian defender, sent off last Saturday for retaliating against Chelsea's Spain striker Diego Costa, had his dismissal rescinded but was handed a one-match ban on Friday after admitting an FA charge of improper conduct.
Gabriel was fined 10,000 pounds ($15,174.00) and suspended for failing to leave the pitch quickly enough.
Costa, who appeared to have escaped with a yellow card, was subsequently banned for three matches but that did not pacify Wenger, who said that it repaired only "five per cent" of the damage his team suffered by losing Gabriel before halftime.
"Ideally, we want the right decision to be taken during the game. We should have played with 11 against 10 but instead we played with 10 against 11," Wenger told a news conference.
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After their 2-0 defeat at Stamford Bridge, Arsenal won a League Cup tie 2-1 at their greatest rivals, Spurs.
They will also be without injured midfielder Francis Coquelin for Saturday's trip to Leicester, the only unbeaten team in the league.
Claudio Ranieri's side lie one place and two points above Arsenal in fourth position.
"It shows we have a strong squad," Wenger said of the win at Tottenham. "We showed how to fight on Wednesday night. The game was about commitment and mental resources which we showed.
"I have great confidence in these players."
That includes Chile forward Alexis Sanchez, last season's leading scorer for the club, who is without a goal so far in the new campaign.
"It takes time to settle and come back to your best," Wenger said. "I'm not worried about Alexis Sanchez and I'm confident he will score."
(Reporting by Steve Tongue; editing by Sudipto Ganguly)
