But former Potters star Seyi Olofinjana equalised with a curling effort before Stoke's Abdoulaye Faye saw red.
BBC: Hull 2-1 Stoke
2.
Kevin McDonald hit back for Scunthorpe from 18 yards before Dany N'Guessan converted Jon Forte's cross, but Seyi Olofinjana settled Cardiff nerves.
BBC: Scunthorpe 2-4 Cardiff
3.
Hull completed their first summer signings on Thursday by bringing in midfielder Seyi Olofinjana from Stoke and Villarreal striker Jozy Altidore on loan.