The Gunners' 6-0 win was the biggest ever victory by an English team against a French opponent in European competition.
Two late goals by 19-year-old Nico Paz and Joselu gave Real Madrid a 4-2 fightback win against Napoli on Wednesday, securing the top spot in Champions League Group C with one round of matches remaining.
Rasmus Hojlund's brace fired United to a brilliant start but Ten Hag's 10-man side gave up their two-goal lead after Rashford's dismissal in the 42nd minute -- and now United, who have already been eliminated from the League Cup and are a lowly eighth in the Premier League, are on a Champions League knife edge with two group games left to play.
Real manager Carlo Ancelotti rested several regular starters, including top scorer Jude Bellingham with a shoulder injury, but the 14-times champions maintained their 100% record to lead Group C with 12 points from four games.
Successive defeats in the League Cup and Premier League had halted Arsenal's momentum but goals by Leandro Trossard and Bukayo Saka cemented their place as leaders of Group B.
AC Milan winger Christian Pulisic has backed his team to turn around their mediocre Champions League form after the Italian giants suffered a 3-0 defeat against Paris St Germain on Wednesday.
Newcastle United's first defeat of their Champions League return could prove an expensive one with injuries adding to manager Eddie Howe's frustrations at their 1-0 loss to Borussia Dortmund at a rainy St James' Park on Wednesday.
Feyenoord took over top spot in the standings on six points after a 3-1 win at Lazio earlier on Wednesday and the draw left Atletico second on five points, one clear of Italy's Lazio in third. Celtic are bottom with one point from three games.
Pep Guardiola's side maintained their 100% winning record in Group G with three victories, despite their pre-game concerns about playing on the slick artificial turf at rain-lashed Wankdorf Stadium.
Academy graduate Lewis, who made 23 appearances for City in all competitions last season, was among the Premier League club's best attacking outlets on Wednesday and set up Phil Foden's 25th-minute opener.
Substitute Ferran Torres scored to give Barcelona a hard-fought 1-0 win at Porto in their Champions League Group H clash on Wednesday, with the Spanish side finishing with 10 men after Gavi got a second yellow card for a foul in added time.
A rampant Newcastle United put in a stellar showing to secure a superb 4-1 victory over French champions Paris St Germain in their first Champions League home match in 20 years on Wednesday.
The England midfielder, who moved to Madrid from Borussia Dortmund in June, netted his sixth goal in six games this season.
The German side struck twice in four minutes in the first half at the Allianz Arena to set them on their way to a 4-3 victory in their Group A opener.
Arsenal manager Mikel Arteta said they used the emotion of Wednesday's return to the Champions League in the right away as they ruthlessly dispatched PSV Eindhoven 4-0.
"There are many. Inter are a team used not only to defend. There is a belief that Italian teams only know how to defend, but Inter can do many other things," a relaxed Guardiola told reporters on Friday.
City will be favourites against the Italian side, a situation they also found themselves in against Chelsea in the final two years ago, only to surprisingly lose.
Puyol says that while City, like Guardiola's Barcelona sides, are blessed with attacking options, they also have the same defensive discipline.
Pep Guardiola's side have wrapped up a fifth Premier League title in six seasons, beat Manchester United to win the FA Cup last weekend, and could be crowned European champions for the first time with victory over Inter in Istanbul.
"No worries (about Salah's future)... Obviously Mo loves being here and Mo was part of it. He said apologies for what 'we' did, not apologies for 'what the other guys did, but I had to go with them'. Not at all, it's all fine," Klopp said.