Motherwell took the lead with a counter-attack after goalkeeper Graeme Smith had punched clear a Lyle free-kick and then palmed away a Chris Swailes header.
"Lee was fouled right on the edge of the box, I don't think it was a penalty but it's certainly a free-kick and within two seconds they've played the ball on the counter-attack and we're down to 10 men, " said Coyle.
However, Balshaw ran back a poor kick and found acres of space before Simpson-Daniel cruised over for a superb counter-attacking score which Paterson, on for Lamb, converted.