The 24-year-old German produced two clinical finishes after the break as Arsenal accelerated to a 5-0 victory that sent a powerful message to Liverpool and Manchester City.
Chelsea could be without top scorer Cole Palmer for Tuesday's clash away at Premier League leaders Arsenal with the forward struggling to recover from illness, manager Mauricio Pochettino said on Monday.
"It was a tough week for us, few tough results and emotionally really hard but we had to keep doing. Today was all about bouncing back and getting the win."
"We were very close, that is the reality. It's painful, but we have to learn from this. We had our moments, especially in the first half," Arteta said.
Arsenal, who have never won the Champions League, travel to the home of Bayern with little time to lick their wounds, targeting their first semi-final in the competition since 2009
Manchester City hold the destiny of the Premier League title in their hands after Arsenal and Liverpool stumbled to shock defeats on Sunday.
Arteta's side would have gone back to the top of the table with a victory at the Emirates Stadium.
Arsenal's Premier League title hopes suffered a massive blow as Aston Villa struck twice in the closing stages to boost their top four bid with a dramatic 2-0 win at the Emirates Stadium on Sunday.
Pep Guardiola said Manchester City are in a privileged position to be fighting to defend a treble of trophies after beating Luton 5-1 to go top of the Premier League on Saturday.
The former Tottenham striker enjoyed a prolific record in north London derbies and a summer change of scenery made no difference.
Tuchel's team are on the brink of surrendering the German title for the first time in 12 years after a brutal domestic campaign.
The super computers and number crunchers still don't fancy Arsenal's chances of winning a compelling three-way Premier League title race despite, on current form, the London club being the best team in England.
"We're all buzzing, we know the win takes us back on top. We're building momentum," said Saka.
"I've been in the tunnel playing in a different shirt and looking at the Invincibles, You had a feeling 'tonight is going to be really tough'. Hopefully we can create that," Arteta said
Alexis Mac Allister fired Liverpool back to the top of the Premier League as the Argentine's "wonder goal" inspired a tense 3-1 win against lowly Sheffield United on Thursday.
Mikel Arteta praised his bit-part players after they helped take Arsenal back to the top of the Premier League with a 2-0 victory over Luton Town on Wednesday.
Mikel Arteta said Tuesday that Arsenal may have to win all of their nine remaining Premier League games if they are to be crowned champions as he prepares for the "most beautiful part of the season".
Manchester City manager Pep Guardiola insisted his team are the ones to beat in the tightest Premier League race for years even though they remain third in the standings following a goalless draw with rivals Arsenal on Sunday.
Manchester City failed to break down Arsenal as a highly-anticipated clash at the top of the Premier League failed to live up to the hype in a 0-0 draw at the Etihad on Sunday.