Southampton fired manager Russell Martin late Sunday after the Premier League's last-placed team was thrashed 5-0 by Ange Postecoglou's Tottenham.
Southampton has only won once in the league this season and is nine points adrift of safety.
Saints fans started to leave St Mary's Stadium after 25 minutes against Tottenham when they were down 4-0.
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Ange Postecolgou and Russell Martin after the 5-0 result. Getty
James Maddison scored inside the first minute, before Son Heung-min, Dejan Kilusevski and Pape Matar Sarr all added further blows.
Maddison's second right on half-time was the final dagger.
It was a welcome relief for Postecoglou who has been under significant pressure but a significant blow for his rival.
“We can confirm that we have taken the difficult decision to part ways with our men’s first team manager, Russell Martin,” the club said in a statement.
The decision came on the same day as another relegation-threatened team, Wolverhampton, fired head coach Gary O’Neil. Wolverhampton is second to last in 19th and four points ahead of Southampton.
James Maddison celebrates Spurs' win. Getty
Martin led Southampton up to the Premier League last season but has been unable to turn round a a woeful run of form at the start of this term and his team lost five of its last six games.
“The board have supported Russell and his staff and been open and transparent regarding our expectations,” the club said.
“We have all been on the same page in recognizing the urgency of needing results to improve.”
The club said its under-21 team manager Simon Rusk would take over on an interim basis.