The Frenchman was expected to sign a world-class forward such was the belief that, without one, the Gunners could not challenge for the Premier League title.
However, Wenger ultimately opted not to do so, which lead to considerable scrutiny and questions of his decision-making at the Emirates.
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And whilst the jury is still out over whether the 65-year-old made the right decision, it would seem the faith he held in Walcott was not misplaced.
The Englishman has seized the opportunity to spearhead Arsenal's attack with both hands since stepping in for the hit-and-miss Olivier Giroud, with a string of strong performances.
Fine finishes against Leicester City and Olympiacos, followed by a superb display in the Gunners' 3-0 demolition of Manchester United at the beginning of October, encapsulated Walcott's potential in the lone striker role.
On Walcott's rise to form, Wenger said: "At the start of the season, I faced questions from everybody: 'Why don't you buy a central striker?'
"So sometimes you have to have strong beliefs and show the players as well that you believe in them in that position.
"I always said that he will play through the middle and he got his knee injury when he played well through the middle against Tottenham. It took him a while to come back, I must say.
"But now in the last two games, the last few games, he looks always dangerous in this position. The quality of his movement is outstanding and he has found his finishing again.
"Now against Man United, he has also found his commitment back."
Wenger will hope that Walcott's - and indeed his whole team's - rich vein of form continues when they face Watford at Vicarage Road on Saturday evening.
The Gunners currently sit second in the Premier League, two points behind leaders Manchester City, with this season presenting arguably their best chance of winning the title, given the Citizens' irregular form, Chelsea's struggle to find their feet and United's ongoing transition.
Arsenal fans - is Theo Walcott the answer to Arsenal's need for a world-class striker? Let us know in the comments below!