The four-goal thriller game ended 2-2 with both teams sharing points at the Emirates.
Man United manager Erik ten Hag admitted his side displayed a horror show in the opening minutes of the match.
Arsenal kept their title dream alive on Saturday after they beat Bournemouth 3-2 at the Emirates Stadium.
It was Arsenal’s third defeat in the league this season, with Manchester United and Everton the other two clubs to overpower the Londoners.
Arsenal failed to extend their lead atop the Premier League table after they were held to a goalless draw by Newcastle United at the Emirates Stadium.
With 40 points in 15 games, Arsenal are now seven points ahead of Newcastle, who earlier on Monday beat Leicester City.
Kaoru Mitoma and Tariq Lamptey were both on target in the second half as Arsenal were knocked out of the English League Cup in the third round.
Both teams have qualified to the knockout stage of the competition but the final standings will be determined on the final day of the group stage.
Arsenal secured their spot in the Europa League knockout stage with two games to spare after beating PSV Eindhoven 1-0 on Thursday.
The Gunners win against Spurs is a bold statement of their readiness to contend for the title this season.
