The Arsenal goalkeeper believes the French striker's loan success marked a turning point in the Gunners' season, aiding in their eventual push for Champions League qualification
Henry returned to the Gunners on loan from the MLS club New York Red Bulls for a brief but successful period in which he scored the winner in his first match back against Leeds United in the FA Cup and the winner in his final Premier League match against Sunderland.
"If you’re talking about turning points you have to give credit to one man, and I mean Thierry. When he came here, wow, it was something different.
"It was priceless to have someone around who’s been here, done it and was the best player in the world at one point.
"When he scored the winner against Leeds, the buzz around the stadium was the biggest I've ever felt – and I think it had a big impact on the players too. Going into the dressing room afterwards and seeing everyone so happy for Thierry was a really big moment.
"Then he scored the winner at Sunderland in his final game for us. That was the one that turned the season around in my opinion, coming back from 1-0 down and Thierry scoring at the end. Things like that give you confidence and simply put you in a better mood."
Following victory away at Sunderland, Arsenal went on to win their next five Premier League matches, including a memorable victory against arch rivals Tottenham, in which they came from two goals down to win 5-2.
Looking back on the success that stemmed from Henry's goal, Szczesny credits that moment as one of the main turning points which revived the Gunner's flagging hopes of Champions League qualification.
He continued: "It's not something you think about but subconsciously you feel better, you want to work hard, you can’t wait for the next game to come.
"If you're in that kind of mindset, thinking 'When’s the next game? I want to play now!' then when the time comes you're in the right frame of mind to win it.
"We went on a great run and from being behind Tottenham we went in front of them. I can't say it made our season successful, because I don't count it as a success without winning a trophy, but it definitely saved it a little bit."