Sadio Mane bagged a hat-trick in a vibrant display of attacking football from Southampton that swept aside Manchester City 4-2 and left the visitors facing a scramble to secure Champions League qualification.
The defeat three days before their semi-final second leg against Real Madrid left City manager Manuel Pellegini admitting he felt very frustrated.
"I didn't expect that performance, especially in defence," he said.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"The best way to prepare is to win but we couldn't do it."
The result was never in doubt from the moment Southampton forward Shane Long capitalised on a Dusan Tadic assist in the 25th-minute.
The Serb also set up two of the goals for Senegalese striker Mane who pounced after 28, 57 and 68 minutes to complete his second hat-trick of a prolific season which has yielded 14 goals.
Although City countered with a brace from Kelechi Iheanacho in the 44th and 78th minutes, Saints never let their grip slip on a victory that kept them in the hunt for a Europa League place.
Southampton manager Ronald Koeman was delighted after his team had climbed to seventh in the table, two points behind West Ham United.
"We fight for Europe and that's what we like," he said. "Two games to go and we're still fighting for something."
Fourth-placed City lead Manchester United by just four points and their neighbours have a game in hand.
(Reporting by Neil Robinson, editing by Ed Osmond)
