Despite second half chances, a goal in each half for St Johnstone consigned United to defeat. Steven Anderson's header gave St Johnstone the lead before Stevie May's tap in wrapped up the points.
The hosts started strongly and continued in that vein for most, if not all, of the first half. Steven Anderson tested Radoslaw Cierzniak early on with a volley and David Wotherspoon had a cross cleared by Keith Watson shortly after.
St Johnstone took the lead after 32 minutes. Wotherspoon despatched a free kick from the left towards the back post. Anderson rose unmarked and headed the ball past Cierzniak.
Despite endeavour, United couldn't really test Allan Mannus in the St Johnstone goal. However, the hosts almost doubled their lead when Stevie May hit the post with a shot from outwith the area.
The second half sparked into life for United with the inclusion of Ryan Dow from the bench. Despite two good chances from him and further efforts from Brian Graham as well as Gary Mackay-Steven it would be Stevie May who would find the back of the net to seal the points for St Johnstone. Dave Mackay advanced down the right and although Keith Watson got to the cross at the first attempt, it was May who reacted quickest and forced the ball across the line.
St Johnstone: Mannus, Mackay, Cregg, Wright, Anderson, MacLean, Wotherspoon (Thomson 89), Dunne, May (Miller 85), Easton, O'Halloran (Hasselbaink 77).
Subs not used: Banks, Brown, Clancy, Iwelumo.
Dundee United: Cierzniak, Gunning, Paton, Rankin, Armstrong, Mackay-Steven (Graham 83), Watson, Gauld (Dow 61), Souttar, Ciftci, Robertson.
Subs not used: McCallum, Dillon, Wilson, Gomis, El Alagui.
Referee: John Beaton
Assistant Referees: Charlie Smith, Sean Carr.
Fourth Official: Bobby Madden
Attendance: 5,223