Going clear on board his 13-year-old stallion Royal Rose II, he finished almost three seconds faster than Gerard Clarke (IRL) in second. Steven had never won a class before in the International Arena at Hickstead, although he's been enjoying a particularly successful run - winning 15 international classes in the past 12 weeks.
"I had a point to prove, after last year in the Derby when the commentator described me as a 'failed rider'," said Steven.
Steven is part of the famous Whitaker showjumping dynasty - he is brother to top riders Michael and John, and father to Ellen. Steven has always ridden and competed, but in recent years has focused on training his daughter.
"Ellen has been asking when she can get the ride back [on Royal Rose II], and then if I'll tell her how to ride him," he added.
Jane Annett from Kent was delighted with her win in the afternoon's main class, the Bunn Leisure Derby Tankard with Zidane V.
She said: "I thought the ground was superb and held up very well in the international arena, and Zidane V loved the going."
Zidane V, a 10-year-old gelding, was originally a dressage horse but he proved far too naughty for it and went to Jane as a showjumper.