National swimmer Quah Zheng Wen won the men's 200m butterfly event at the Spanish Open on Saturday with a time of 1min 56.85sec.

It was also under the 'A' qualifying time of 1:56.97 for the 2016 Olympics in Rio and continues the 18-year-old's remarkable rise as he looks set to challenge Joseph Schooling as Singapore's biggest swimming star.

Zheng Wen's victory in Malaga also happened on the same day when Schooling, a student at the University of Texas, claimed his first individual NCAA title by winning the 100-yard butterfly final at the 2015 Men's National Collegiate Athletic Association (NCAA) Division I Swimming and Diving Championships.

Schooling's time of 44.51 seconds in Iowa was the second-fastest short-course time in NCAA history, behind Stanford's Austin Staab's 44.18 effort in 2009.

Both Zheng Wen and Schooling will go head-to-head in the 50m, 100m and 200m fly events at the SEA Games in June with both qualifying as Singapore's fastest swimmers.

Zheng Wen's time in the 200m fly was the sixth-fastest recorded this year and faster than Schooling's bronze-winning time of 1:57.54 at the Asian Games in Incheon last year.

Schooling still holds the national records in all three distances, including the 200m fly in 1:56.27 which he set at the Fina World Championships in Spain in 2013.