The Tigers, who spent the week in the south of France on a pre-season camp, led 4-0 at half-time thanks to a try from centre James Evans.
Kane Bentley and Cyril Stacul replied with tries for the Dragons after the break and William Barthau kicked two goals but a second-half conversion from Castleford forward Craig Huby proved the difference between the two sides.
New Wigan coach Michael Maguire enjoyed a remarkable success in his first match in charge as the Warriors overcame a 14-point deficit with three tries in the final nine minutes to snatch a 40-38 victory at Wakefield.
Wakefield, who raced into an early 12-0 lead, looked to have secured the win after running in eight tries in the first three quarters but Danny Brough could manage only three conversions.
The Wildcats led 22-18 at half-time courtesy of tries from Dale Morton (two), Sean Gleeson, Glenn Morrison and Daryl Millard and a solitary goal from Brough.
Gleeson added a second try in the second half and Aaron Murphy and Kevin Henderson also touched down as the home side established a 14-point lead.
The visitors finished strongly, however, with Darrell Goulding scoring two tries and fellow centre George Carmont also touching down in a late flourish, with Cameron Phelps adding two conversions.
Wigan's earlier tryscorers were Sean O'Loughlin, Mark Riddell, Eamon O'Carroll and Pat Richards, who also kicked four goals. The Warriors were without new scrum-half signing Paul Deacon, who is troubled by a wrist injury.