Bedene cruised through the first set and had break points in the second, but Rosol went on to win 1-6 7-6 (8-6) 6-3.
The result prevents Slovenia-born Bedene from breaking into the top 50, having risen to a career-high 54.
Meanwhile, Tomas Berdych captured his 11th career ATP title by beating Spain’s Guillermo Garcia-Lopez in the rain-delayed Shenzhen Open final.
Held over until Monday because of heavy rain that drenched parts of southern China over the weekend, Berdych maintained his composure to win in straight sets 6-3 7-6 (9-7).
Briton Johanna Konta, 24, has moved up to a career-high WTA ranking of 49 following her recent run of 21 wins in 22 matches until her quarter-final defeat to Venus Williams at the Wuhan Open last week. She has now gone above Heather Watson, who is at 62 in the rankings.