Arsene Wenger's side dominated against the Tigers at the Emirates Stadium on Saturday afternoon but, unlike their FA Cup final meeting in 2014 and last year's third-round tie, they could not find a way to beat Steve Bruce's men.
Hull goalkeeper Eldin Jakupovic made several good saves to keep Arsenal at bay, with a replay not what either side would have been particularly keen on given their respective targets this season.
While Hull are gunning for promotion straight back to the Barclays Premier League, FA Cup holders Arsenal are challenging for the title.
They also have a mouth-watering Champions League first knock-out round clash with Barcelona on Tuesday - and Mertesacker wants to see an improvement from the attacking unit when the Catalan giants come to town.
"Overall, we missed a bit of something and we have to come back quickly in three days time," he said.
"We have a very important game, the first leg against Barcelona, and we will see the fans again, it will be another buzzing night but it is up to us how we perform.
"It is down to us, we produced a good defensive performance but overall in the final third, that little final pass at the end, we always rushed ourselves at times to finish so we need to learn from that.
"We had a couple of good chances and we couldn't keep the pressure as high as we wanted, especially in the second half.
"We had enough chances to win, but we were unlucky at times
Overall it was disappointing, especially our finishing
We allowed (Jakupovic) to make some decent saves because we were not that decisive."
While Mertesacker was left bemoaning Arsenal's inability to see off Hull, Tigers boss Steve Bruce hailed the result as a highlight of the club's FA Cup history.
Bruce, who led Hull to Wembley for the 2014 final and saw his side take a two-goal lead only to eventually lose in extra-time, made 10 changes to his team as he keeps promotion his main aim - but he was pleased with how the players who came in fared.
"They've gone out there and produced a fantastic result, probably one of the best results in the club's FA Cup history," he told the club's official website.
"As I've said before, there's a fine divide between playing and not playing and when we can make ten changes like we did against Arsenal and then get the performance we did, you realise the squad that we've got.
"To come to the Emirates a get a draw against the mighty Arsenal is terrific."
Source : PA