Third Division Albion Rovers dumped Partick Thistle out of the Challenge Cup with a deserved win at Firhill.
The minnows took just three minutes to sting Thistle with a scrambled goal from Martin McBride.
Thistle drew level after 21 minutes when Brown Ferguson rose above Gordon Lennon to flick Scott McCulloch's corner into the roof of the net.
But the Wee Rovers came storming back seven minutes later when Chaplain raced into the box to shoot home.
Partick Thistle: Arthur, Sives, Boyd, Robertson, McCulloch (Strachan 65), James Gibson, Brady, Ferguson, Billy Gibson (McConalogue 82), Donnelly, Graham Gibson. Subs Not Used: Samuchonga, Kane, Hodge.
Booked: Brady. Goal: Ferguson 21.
Albion Rovers: Ewings, Moffat, Ciaran Donnelly, Lennon, McGhee, Doyle, Chaplain, Friel, McBride (Cleary 88), Felvus (Walker 73), Savage (Chisholm 65). Subs Not Used: Thompson, Creaney.
Goals: McBride 3, Chaplain 28.
Ref: C Hardy