The 26-year-old, who was making his first start of the season, provided the assist for Peter Whittingham's winning goal against the Baggies in South Wales.
"Craig is someone I love having at the club," Goal.com quotes Mackay as saying. "He's got a real enthusiasm for football. He's got great potential, he knows he has to add to his game but sometimes he can be unplayable."
Cardiff continue their Premier League campaign next Saturday when they face Liverpool at Anfield.