And that gives hope to Manchester United fans - as well as supporters of West Ham United.
Indeed, the east London side are eight points behind Arsenal with a game in hand over Arsene Wenger's men. That's a big gap - but certainly not an insurmountable one.
Henry told Sky Sports on Sunday afternoon: "It is very much alive [the race for the top four].
"They [Arsenal] didn't do enough offensively to win the match and you can't say they deserved to win the game."
The Hammers' chances of finishing in the top four are, of course, very slim. Should West Ham win their game in hand, they'll still be up against it with Arsenal, Manchester United and Manchester City all also vying for the Champions League places.
But Henry is right in that the race is wide open. The Gunners aren't looking lethal in front of goal and nor are Manchester United.
United themselves will certainly draw hope from Arsenal's slip up. They should still make the top four... but both Man United and West Ham will be waiting to pounce on any mistakes.