Dimitrov had previously won in Acapulco where he defeated Andy Murray in the semi-finals.
Initially, he struggled against big-hitting Rosol in the first set, but managed to wrap up the first set in 58 minutes in spite of a tie-breaker.
He then maintained the momentum in the second set to move on to his 20th match win in 2014, Sport 24 reports.
Dimitrov, who now has three career titles, said that he felt good after his win over Rosol whom he described as a very good player capable of hitting some outstanding winners.
Dimitrov had earlier entered the final after semi-final French opponent, Gael Monfils, retired within 16 minutes with an injury.