We doubled our lead shortly after half-time as Emile Smith Rowe was on hand to score his second senior goal for Arsenal from close range after Carl Jenkinson's cross was palmed away by Mark Howard in the 50th minute.
The sending off for Guendouzi means he'll miss Saturday's Premier League home match against Liverpool.
We will be watching to see the miracle coach Unai Emery will perform against Jurgen Klopp when they meet.
Emery was suitably anxious to introduce club record signing Pierre-Emerick Aubameyang from the bench for the last 15 minutes.More news: Saint Mark's Square Underwater After Flooding in Venice
"In each moment for each match, we are going to give the goalkeepers the opportunity to help us", Emery said.
"I have had a good rest and watched football a lot".
"I could not believe it when he pulled out the red because we had got back in the game and we were in the ascendancy".
Petr Cech made his return after a month out with a hamstring injury, but he endured a hard day and nearly gifted Blackpool a goal when he was robbed in his own penalty, only to be bailed out by the offside flag when Nathan Delfouneso found the net.More news: Pakistan frees woman facing death penalty for blasphemy
The English Premier League will be back this weekend when Liverpool travelling to Emirate Stadium to play against Arsenal for their eleventh match of the season.
But Emery will not abandon his principles with respect to playing out from the back, convinced Cech can do well.
"After that, I'm a supporter like anyone else - I want them to win football games'". He has experience. He can do good.More news: Chelsea icon Frank Lampard claims Eden Hazard is better than Lionel Messi