Southampton secured their Premier League status for another year after a thrilling 3-3 home draw with Bournemouth on Saturday as Cardiff City slumped to a 1-0 defeat at Fulham.
The draw put Southampton in 16th place on 38 points, seven ahead of Cardiff and four clear of Brighton & Hove Albion with two games left to play.
"It was a crazy game, we are very happy now. It was a tremendous match," Ralph Hasenhuettl told reporters after steering his club to safety.
Fresh from scoring the fastest goal in Premier League history against Watford, Irish striker Shane Long again got Southampton off to a flying start with a goal in the 12th minute, but Dan Gosling equalised eight minutes later.
Long missed a sitter in the 24th minute, stabbing the ball against the post with the keeper stranded and the goal at his mercy, and it was to prove costly as Callum Wilson pounced to rattle home a rebound in the 32nd minute.
James Ward-Prowse put the Saints level with a skimming shot that flew in at the foot of the post 10 minutes into the second half.
They were interrupted when Wilson scuffed home his second goal, but news that Cardiff had gone behind to Fulham had filtered through to the ground and Southampton were able to enjoy confirmation of their survival in the top flight.
Southampton had nine points after winning just one of their opening 15 games when Austrian coach Hasenhuettl took over from Mark Hughes in December, and the 51-year-old went on to guide them to eight wins and five draws in 21 league games at the helm.
"We deserve this, we invested a lot in this time and learned a lot. We showed how beautiful we can play," he told reporters, adding that he would be aiming to rebuild his squad during the summer.
"The next step must be to get more clinical in some situations. Two games before the end, to be clear [of relegation] is fantastic for us."