The overcast conditions and threat of bad light saw Oakham skipper Chris Larsen and Overton captain Paul Thwaites agree to reduce the match to 18 overs per side.
Oakham, playing on home soil at the Lime Kilns, won the toss and Larsen chose to bat.
The hosts failed to gather any real momentum throughout their innings with wickets falling at regular intervals as they stumbled to an undaunting 103.
With the run-rate set at just 5.7 per over Overton knew they would not need to take to many unneccesary risks but still managed to lose wickets cheaply.
Tom Flowers and Yathagode both fell early and Oakham looked to be gaining the uppper hand until the ever-impressive Brian Makwana arrived at the crease.
Makwana, who had bowled and taken on the role of wicket keeper at different points in the match, made a fabulous unbeaten 45 to guide Marko to the title in the final over.
He was very ably supported by Mark Matthews and skipper Paul Thwaites during his knock.
The victory not only gave Marko the title but £500 of Kookaburra equipment.
Thwaites said he hoped the cup triumph would lead to even more success for the club.
He said: "We enjoy the format Twenty/20 and I won't be surprised if the 45 over game is eventually replaced by this format because it's exciting to watch and great to play in.
"I'm delighted that we've achieved this because we're working hard at the club to bring success and start a bar with social evenings.
"Every credit to Oakham because they won it last year and are a very good side with a great set-up but I think we deserved the win."
Larsen agreed but said his side hoped to regain the crown in 2009.
He added: "We fell short in terms of runs and we put down too many chances.