The top four sides at the end of the Premier League season will gain entry into Europe's leading club competition.
Naby Keita bagged Liverpool's fastest ever Premier League goal before Sadio Mane and Mohamed Salah also got on the scoresheet.
A much-needed win moved Ole Gunnar Solskjaer's men up to fifth.
Mauricio Pochettino's side would have moved within two points of leaders Manchester City with a win at Turf Moor.
Gonzalo Higuain showed why he has a stellar scoring record over the past decade in Spanish and Italian football with two excellent finishes to open his Premier League account.
Tottenham Hotspur beat Newcastle United 1-0 while London rivals Chelsea outclassed Huddersfield 5-0.
Manchester City reduced Liverpool's lead at the top of the Premier League table to four points.
Arsenal overcame a resolute Huddersfield to stretch their unbeaten run to 21 games.
The video of a teenager attacking a Syrian refugee boy at school has gone viral on social media.
Huddersfield halted an eight-game home run without a top-flight goal and moved above Fulham and Cardiff at the foot of the table.
In the 24th minute, Mohamed Salah steered in Xherdan Shaqiri's pass to score his 50th goal in English club football.
Aguero, who turned 30 in the close-season, has now scored 14 times in his last eight Premier League games at City's Etihad Stadium.
Chelsea opened their Premier League campaign with victory against Huddersfield, while Tottenham, Bournemouth, Crystal Palace and Watford also made winning starts.
The fee for the 26-year-old winger, the son of former Manchester United and England midfielder Paul Ince, could rise to 12 million Pounds.
Arsene Wenger was overcome with emotion before and after Arsenal's last game of the Premier League campaign.
Antonio Conte admitted Chelsea had only themselves to blame after their bid to qualify for the Champions League suffered a hammer blow as Huddersfield secured their Premier League survival with a 1-1 draw at Stamford Bridge on Wednesday.
Paul Pogba hasn't completed 90 minutes since a 1-0 win at Burnley just under a month ago.