The striker, now at New York Red Bulls, was part of the Gunners last trophy success - the 2005 FA Cup - but has backed his former boss to end the club's eight-and-a-half-year silverware drought this season.
|5/1||Arsenal are 5/1 with BetVictor to win the Premier League title|
"I think Arsene himself understood that. When you don't have something to show at the end of the season it is difficult to talk and to stop all of the critics.
"But this year he is showing everybody that Arsenal can compete again."
Wenger broke the club's transfer record with the £42.5 million capture of Mesut Ozil from Real Madrid in the summer transfer window.
And Henry feels the Germany international is proving to be a fine piece of business following a return of five goals and nine assists this term.
"When you look at him playing when he has the ball it seems like he has all the time in the world - and I can tell you for a fact it's not that easy," Henry continued.
"He paid the price to have a player like Ozil, but I think that right now it's showing that it's worth it and hopefully in the end it will show more."