The Gunners fell to a 3-2 defeat at Old Trafford as two goals from Marcus Rashford and a deflected second-half effort from Ander Herrera ensured United claimed all three points.
The result means the north Londoners are five points behind Premier League leaders Leicester City, and three behind second-placed Tottenham, and Henry is now unconvinced that the Gunners can recover and win the title.
"That wasn't a performance from a team who want to be champions. That's where, as an Arsenal fan, I'm looking at it, I'm not sure that team can be champions, can they show me they can be champions? Today, they didn’t reassure me on anything.
"The only thing that’s good is that they are still in the title race, other than that they were second best in everything. It was a really poor performance."