Reigning badminton world champion P.V. Sindhu on Sunday crashed to a 12-21, 5-21 defeat to Spanish Olympic champion and world No. 3 Carolina Marin in the final of the Swiss Open Super 300 tournament.Sindhu, who came into the final without dropping a game, matched the Spaniard in the opening exchanges of the first game. Marin took a 2-0 lead early on after which Sindhu made it 2-2. However, after 6-6, Marin started putting distance between herself and her opponent. Sindhu kept her in her sights, however, and Marin was leading 11-8 at the interval in the first game.Marin then came into her own in the second half of the first game, racing to a 15-8 lead before Sindhu pulled two points back. The three-time world champion, however, had her foot on the pedal now and went on to get nine game points with a 20-11 lead.Sindhu managed to win one more point but a backhand error in the next game allowed Marin to take it 21-12.Marin was imperious in the second game, winning the first five points on the trot before a loose backhand gave Sindhu her first point. Sindhu then won the next point with an inch-perfect smash down the line after which Marin raced all the way to lead 11-2 at the interval.She continued winning points after the break until it was 14-2 when Sindhu nibbled back a point. However, the latter would get her next two points only after Marin had reached 19 after which the Spaniard got to a whopping 15 match points. She took the game at her first attempt, thus winning her third title of 2021.Earlier, Denmark's world No. 1 Viktor Axelsen beat Thai eighth seed Kunlavut Vitidsarn 21-16, 21-6 to win his third title of the year in the men's singles final. Malaysia's Tan Pearly and Thinaah Muralitharan beat Bulgarian third seeds Gabriela and Stefani Stoeva 21-19, 21-12 in the women's doubles final while Danish sixth seeds Kim Astrup and Anders Rasmussen beat Germany's Mark Lamsfuss and Marvin Seiden 21-16, 21-11 in the men's doubles final.French sixth seeds Thom Gicquel and Delphine Delrue beat Denmark's Mathias Christiansen and Alexandra Boje 21-19, 21-19 in the mixed doubles final.