George Burley has set his side a target of three wins from the final four games to reach the play-offs.
Defeat at home to Sunderland yesterday saw Saints drop out of the play-off places and down to eighth as the season reaches its climax.
Saints travel to out of form Birmingham on Saturday before playing Leeds at St Mary's, Norwich at Carrow Road and rounding off their season at home to Southend.
Another nine points would leave Saints on 75 for the season and should just about be enough to make the play-offs but any less is likely to spell disappointment.
Burley said: "Win, lose or draw this game, nothing was going to be decided. We've still got everything to play for.
"With four games left, we're probably going to have to win three of them to get in the top six.
"If we can get nine points, we won't be far away from the top six.
"Birmingham away is going to be a tough game next but we've shown we can go away and get the three points."
After two successive away victories, Saints looked like they were going to follow it up at St Mary's when Marek Saganowski gave them a second half lead.
But two strikes from outside the area from Carlos Edwards and Grant Leadbitter inflicted a 2-1 defeat that sent Sunderland to the top of the table.
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