The Gunners forward was overjoyed as Arsene Wenger's side produced a stunning turnaround to progress to the fifth round of the FA Cup
The Gunners trailed by two goals at the break thanks to efforts from Richard Dunne and Darren Bent, but replied with three goals in a 10-minute spell with Walcott getting his name on the scoresheet, alongside Robin van Persie, who struck twice from the penalty spot.
"I enjoyed the second half especially because the team worked so hard," Walcott told ESPN.
“It was absolutely fantastic. This cup is massive and it means a lot to us.
"We want to win the trophy and we need to show the fan’s that we’re ready. It just shows what great character we have in the dressing room."
Arsene Wenger's side had previously lost their last two games and looked on course to extend their poor record until they showed immense resolve to turn the game on its head.
"We’ve got to always believe that we can come back," Walcott added.
"After a very dodgy first half, we just went at them.
"We needed a bit of luck, and hopefully our luck’s changed after that."
Arsenal will now face Sunderland or Middlesbrough in the fifth round, after a 1-1 draw between the two sides on Sunday.