Despite Owen's victories, it still seemed likely that he would be forced to wait for a match with Maguire. However, when the official challenger Wayne Evans declined the opportunity to fight Maguire, stating that he needed more experience, Owen stepped in and the fight was scheduled for November 1977 at the National Sporting Club in London. Maguire was entering the fight on a three-fight losing streak, having suffered defeats to Heleno Ferreira and Alberto Sandoval before unsuccessfully challenging Zurlo for the European bantamweight championship, and Owen was expected to be a serious threat to the Irishman's two-year reign. Owen edged the early rounds of the fight as his longer reach caused Maguire problems and the champion was warned on more than one occasion for use of the head and low blows. Already ahead on points, Owen dominated the eighth round and nearly knocked down Maguire. Such was Owen's dominance, Maguire's promoter Mickey Duff threatened to end the fight. The champion rallied in the ninth round but the referee stopped the fight in the eleventh after Owen had opened a large cut above Maguire's eye. In only his tenth professional bout, Owen was crowned the British bantamweight champion at the age of 21, becoming the first Welsh fighter to hold the belt since Bill Beynon in 1913. He was awarded the belt by Prince Henry, Duke of Gloucester while Maguire subsequently announced his retirement from boxing.