Despite enduring their worst start to a season in 29 years, Mourinho's Blues were the only English team to win in the opening round of Champions League matches, beating Maccabi Tel Aviv 4-0 in Group G as Arsenal lost to Dinamo Zagreb.
"We come with a different feeling
We can wake up with a different state of mind," Mourinho told Chelsea TV.
"Saturday is a big match, it's a great rival
This result can put us in a better situation."
After successive defeats to Crystal Palace and Everton either side of the international break, leaving Chelsea with four points from their opening five games, Mourinho could not contemplate another loss for the Premier League champions.
"We had too many bad results
We couldn't have this one on top of it," he added.
Radamel Falcao could return from a minor injury against the Gunners, but Willian (hamstring) joins Pedro (knock) in missing the clash
Oscar (knee) is a doubt.
As Chelsea aim for a much-needed domestic boost, Mourinho reflected on a positive start to European action ahead of the next round, which takes him to former club Porto.
"Two years ago we lost against Basle, last year we drew against Schalke," Mourinho said.
"In both situations (we were) under pressure to have to go away and recover points immediately.
"To win at home the first game is important
Porto and Dinamo one point each, so it was a good result for us."
Ruben Loftus-Cheek impressed in midfield for a Chelsea side showing six changes from the one which began the Everton loss.
It will be intriguing to see if the 19-year-old keeps his place against the Gunners, or if Nemanja Matic is restored.
Captain John Terry, right-back Branislav Ivanovic and striker Diego Costa were also omitted from the starting line-up.
Costa came on to score one of the four goals, with Willian, Oscar, with a penalty, and Cesc Fabregas also on target.
Mourinho denied suggestions - made by Steven Gerrard - of a rift with Terry but may not restore all of his established stars against Arsenal.
He will consider his options on Thursday and Friday before the lunchtime kick-off, with Loftus-Cheek having given him something to think about.
Loftus-Cheek said: "I really enjoyed the occasion
I think we played some really good football and it's a big lift for us going into the weekend.
"We had to win from the previous results
We had to give our best.
"We'll take the confidence and hopefully carry it on into the weekend."
Source : PA
Source: PA