The 27-year-old Englishman carded 18-under to hold off compatriot Oliver Fisher at the Doha Golf Club.
And Pepperell admitted he was ready for a big red wine session after four days in the heat of Qatar.
Pepperell told Sky Sports: “I need a glass of wine and more than that I think!
“What a day. Oli made it really tough and I made it tough for myself at the end there with the second shot on 18. I felt good all day, I was in a great place mentally and kept telling myself I’m going to win this and Oli certainly made life more interesting.