Kai Havertz and Ben White scored twice as Arsenal thrashed Chelsea 5-0 on Tuesday to surge ahead in the Premier League title race and ramp up the pressure on Liverpool and Manchester City.
"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.
Mikel Arteta admitted Arsenal paid the price for making one big mistake as Bayern Munich's 1-0 victory sent his side crashing out of the Champions League on Wednesday.
Arteta's side would have gone back to the top of the table with a victory at the Emirates Stadium.
Arteta's side ensured their quarter-final clash remains finely balanced thanks to Leandro Trossard's late equaliser in the first leg at the Emirates Stadium.
Arteta's side have endured a series of chastening defeats against Bayern over the last decade, but Arteta expects them to reverse that trend in Tuesday's quarter-final first leg.
"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
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.
Manchester City can set themselves up to succeed once again on multiple fronts and lift their confidence for the season's run-in with a win over title rivals Arsenal in Sunday's blockbuster Premier League clash, midfielder Rodri said.
The Premier League returns this weekend after the final international break of the season, with a headline fixture on the cards as reigning champions Manchester City host Arsenal on Sunday.
Porto manager Sergio Conceicao said Arsenal boss Mikel Arteta insulted his family during the London club's penalty shootout win over the Portuguese side in their Champions League last-16 tie on Tuesday.
"A magic night. We expected a really tough opponent. It's very difficult to generate momentum and that's credit to (Porto)," Arteta told reporters.
The Premier League's top three are separated by a single point with 10 games remaining as a thrilling battle between Arsenal, Liverpool and Manchester City looks set to go to the wire.
The Gunners are aiming to win a first league title in 20 years.
Liverpool captain Virgil van Dijk said a 1-1 draw against Manchester City, that left three sides separated by just one point at the top of the Premier League, was "bittersweet" for the depleted Reds.
The Gunners have not reached the last 16 of the Champions League for seven years and last made it to the quarter-finals back in 2010.
Bukayo Saka scored either side of halftime as Arsenal crushed second-bottom Burnley 5-0 at Turf Moor on Saturday to go second and keep the pressure on Premier League leaders Liverpool.
Mikel Arteta says title-chasing Arsenal have "learned a lot of things from last season" as they chase a fifth straight Premier League win against Burnley on Saturday.