The Nottingham professional built a deserved advantage as he started and ended the opening session of the day on a high note to lead his Irish stablemate 4-3 with a possible 10 frames to play.
Hamilton, who knocked out the Yorkshireman Jimmy Michie in the opening semi-final on Saturday, was quickly into his stride in a game delayed by 30 minutes because of television commitments involving Sky's coverage of the FA Cup semi-final between Manchester United and Arsenal at Villa Park.
The delay meant that many of the crowd had been waiting for nearly an hour at the Plymouth Pavilions before the first ball was struck.
However, the first frame proved to be worth the wait as Hamilton, the world No 11, opened with a break of 24 and then added a run of 110 to take the lead. He surpassed that break in frame two, however, with a 134 total clearance, leaving O'Brien without a point to his name. The unbroken sequence reached 296 points before O'Brien troubled the scorers for the first time. A brief flicker of a smile crossed his face as the crowd applauded the moment.
O'Brien, who beat the world No 1 and world champion, John Higgins, 6- 5 in the semi-final went on to win a 40 minute frame on the pink. He then made it 2-2 with a 57 clearance to the black after Hamilton misjudged a pot on a red. His good run continued with breaks of 45 and 59 to build a 3-2 advantage. But it was Hamilton who finished the stronger with back to back contributions of 61 and 64 to lead 4-3.
That left Hamilton, a quarter-final victor over Stephen Hendry, requiring five of the remaining frames to pocket the pounds 60,000 first prize.Reuse content