Former Coventry winger Leigh Jenkinson's stunning left-foot volley midway
through the second-half and a late George O'Boyle tap-in kept St Johnstone's
European hopes alive.
Although the home side played for 63 minutes with only 10 men after Erik
Pedersen had been ordered off they can have no complaints about this latest
defeat.
The result, coupled with Hibs' surprise point at Parkhead, puts the home side
in the relegation mire and next week's visit to Easter Road takes on even more
significance now.
Saints had failed to register a victory against their rivals this season but
the solid performance saw them run out comfortable winners.
Almost right from the start the visitors were on the offensive and after
Pedersen was booked in the seventh minute a burst of pressure almost gave the
visitors the lead.
In the eighth minute Keith O'Halloran fired in a fierce 25-yarder which forced
Sieb Dykstra into a magnificent save when he touched the ball past the post.
The big keeper again did well when ex-Manchester City defender Alan Kernaghan
let fly from all of 35 yards but, despite a bad bounce Dykstra was on the spot
to save.
Incredibly two minutes later the Dutchman had another good stop when
O'Halloran's 20-yarder was deflected by Mark Perry on its way to goal.
Kernaghan was booked for an off-the-ball clash with Gary McSwegan before
United had their first real chance.
Northern Ireland international Iain Jenkinson threaded a ball through to
Robbie Winters but his ex-colleague Alan Main blocked his close-range effort
with his feet.
In the 27th minute Pedersen was sensationally ordered off for allegedly
elbowing Jenkinson after St Johnstone had refused to give the ball back after
United had played it out for a deliberate throw-in.
The 10 men buckled down however and four minutes from the break McSwegan saw
his angled shot hit the post and bounce clear.
Eight minutes after the interval a determined run by ex-United midfielder John
O'Neil gave Roddy Grant a chance but his shot was blocked by the keeper and
although it broke to Gerry McMahon he attempted to chip the giant Dykstra - and
failed.
United had the ball in the net in the 62nd minute when veteran Maurice Malpas
saw his header chopped off for a previous infringement and four minutes later
Saints went ahead.
A long clearance from keeper Main was headed on by O'Boyle and Jenkinson
wasted no time in planting the ball past Dykstra from 12 yards.
United's Jamie Dolan was booked as United stepped up the search for an
equaliser but the goal came at the other end when Grant saw his shot hit the
post and O'Boyle was on the spot to tap in the rebound from point-blank range.
Teams
Dundee Utd: Dykstra, Jenkins, Malpas, Jonsson, Perry, Pedersen,
Olofsson, Zetterlund (Sinclair 88), McSwegan, Dolan (Gill 83),
Winters (McLaren 75).
Sent Off: Pedersen (27).
Booked: Dolan.
St Johnstone: Main, McQuillan (McCluskey 80), Preston, O'Neil,
Weir, Kernaghan, McMahon, O'Halloran, Grant, O'Boyle, Jenkinson.
Subs Not Used: McAnespie, Andersson.
Booked: Kernaghan.
Goals: Jenkinson 66, O'Boyle 89.
Att: 8,045
Ref: K Bisset (Inverness).