GWANGJU, Korea, Republic Of - Canadian swimmer Maggie MacNeil has won the country's first gold medal at the world aquatic championships.

The 19-year-old from London, Ont., competing on her first senior national team, stunned many observers by winning the women's 100-metre butterfly on Monday.

MacNeil set a Canadian record with a time of 55.83 seconds, 0.39 seconds ahead of Sarah Sjoestroem of Sweden.

Emma McKeon of Australia was third.

Canada now has one gold, two silver and two bronze medals at the two-week long event, featuring swimming, artistic swimming, diving and water polo.