Alan Gow's late winner ensured that Owen Coyle's first game in charge of St Johnstone ended in defeat at the hands of former club Airdrie United.
Willie McLaren latched onto a perfect cross from Kevin Barkey to open the scoring in a rare early Airdrie attack.
Stephen Dobbie levelled things up when he blasted home from 20 yards.
But, after Airdrie's Stephen Docherty and St Johnstone's Ryan Stevenson were sent off, Gow steered home the winner from the edge of the box.
St Johnstone: Samson, Cowan, Dyer, McCann, Anderson (Webb 41), Maxwell, Stevenson, Sheerin, MacDonald, Dobbie (Hay 75), Sloan.
Subs Not Used: Hannah, Bagan, Cuthbert.
Sent Off: Stevenson (90).
Goal: Dobbie 57.
Airdrie Utd: McGeown, Docherty, Lovering, Stewart, McManus, McGowan (William Wilson 63), Barkey, Marvyn Wilson, Gow, Hardie, McLaren (Dunn 88).
Subs Not Used: Vareille, McDougall, Hollis.
Sent Off: Docherty (85).
Goals: McLaren 21, Gow 90.
Ref: C Allan