BOURGOIN-JALLIEU, France (Reuters) - Australian Richie Porte sent a warning to his Tour de France rivals by winning the Criterium du Dauphine's fourth stage, a 23.5-km individual time trial, as Chris Froome struggled on Wednesday.
BMC rider Porte clocked a best time of 28 minutes 7 seconds to beat German Tony Martin (Katusha-Alpecin) by 12 seconds and Spain's Alejandro Valverde (Movistar) by 24.
Belgian Thomas De Gendt (Lotto-Soudal) retained the overall leader's yellow jersey after the solo effort between La Tour du Pin and Bourgoin-Jallieu.
Team Sky's Froome, the defending champion who tipped Porte as possibly his main rival for the Tour, produced a below-par performance as he finished 37 seconds off the pace.
However, results are hard to assess on the Dauphine as top riders usually use it as a Tour warm-up and try not to peak to soon ahead of the gruelling three-week race, which starts on July 1.
Spain's Alberto Contador (Trek-Segafredo) was two seconds ahead of Froome, while last year's Tour de France runner-up Romain Bardet (AG2R-La Mondiale) lost almost two minutes.
Writing by Julien Pretot; Editing by Ken Ferris