Alexis Sanchez scored on his return to the Emirates Stadium as Manchester United saw off Arsenal to reach the fifth round of the FA Cup and extend Ole Gunnar Solskjaer's winning start.
The two most successful sides in the competition's history played out an entertaining Friday night game as United secured a 3-1 win - an eighth straight victory for interim manager Solskjaer.
Sanchez and Jesse Lingard had set the visitors on course for victory before Pierre-Emerick Aubameyang pulled a goal back for the Gunners, only for substitute Anthony Martial to wrap up a comfortable win with a late strike.
Solskjaer retained his perfect record in charge of the Red Devils after making five changes for the cup tie - including starts for fit-again Sanchez and striker Romelu Lukaku.
Meanwhile, the defeat could have further-reaching consequences for Arsenal, who lost central defensive pair Sokratis Papastathopoulos and Laurent Koscielny to injuries as Mesut Ozil came off the bench for his first appearance since Boxing Day.
Petr Cech, making his first start since announcing his retirement at the end of the season, was quick off his line to deny Paul Pogba after he was played in by Sanchez early on.
Arsenal's defence, decimated by injuries over the festive period, received another blow as Sokratis limped off with what appeared to be a twisted ankle with less than a quarter of the game gone - and they soon paid the price.
Sanchez, who was roundly jeered by the home fans who have still not forgiven the 30-year-old for leaving for United last January in exchange for Henrikh Mkhitaryan, would be the man to open the scoring.
Ander Herrera played in Lukaku, whose slide-rule pass set Sanchez through on goal, with the Chilean showing composure to round Cech and finish from a tight angle.
Just two minutes later and the lead was doubled, Herrera and Lukaku again involved as United were allowed to break unchallenged, with Lingard coolly side-footing home another pass from the Belgium striker.
Arsenal responded and pulled a goal back before half-time, Aubameyang tapping home at the back post after an Alexandre Lacazette touch diverted Aaron Ramsey's low cross into his path.
Lacazette then had a decent chance to send the sides in level but could only shoot straight at Sergio Romero after good work down the right by Ainsley Maitland-Niles.
Arsenal were straight out of the traps after the interval as Ramsey's close-range header was tipped onto the crossbar and behind by Romero.
With the hosts chasing the tie, they suffered another setback as captain Koscielny - only recently back from a long-term Achilles injury - was forced off after suffering a gash to the face from a stray Lukaku boot.
United were playing on the counter-attack, and Solskjaer opted to introduce both Marcus Rashford and Martial for the final stages of the game.
Lacazette stung the palms of Romero with a driven strike but Unai Emery's side were soon caught out with men committed up-field.
United broke and Pogba's shot was pushed into Martial's path by Cech - with the France forward making no mistake in securing his side's place in Monday's draw.
A late flashpoint saw Sead Kolasinac and Rashford escape with bookings after the video assistant referee aided Craig Pawson identify the main culprits - but both players could have been sent off for butting heads.
Following Koscielny's treatment on the pitch there were an additional 10 minutes of stoppage time, but United saw the game out with relative ease.