Roger Federer defeated Colombian Alejandro Falla 6-3, 6-3, 6-4 in the opening round.
The 34-year-old giant defeated home hope Alejandro Falla, 6-3, 7-6 (7/4) in the final to celebrate his first title in five years.
The victory speaks a lot as Sijsling had made finals at Australian Open and Vasselin had appeared in the Wimbledon semifinals.
Falla, a Bogota resident, is seeking his first ATP Tour title. The 29-year-old left-hander will face Canada's Vasek Pospisil on Saturday in the hard-court tournament at Centro de Alto Rendimiento. Pospisil beat Italy's Matteo Viola 3-6, 6-3, 6-2.
They will now fight it out with second seeds Edouard Roger-Vasselin of France and Igor Sijsling of the Netherlands in the final.
Sam Querrey beat Alejandro Falla for the second time in less than a week, defeating the Colombian 6-3, 6-3 in a first round match at the US National Indoor Championships on Tuesday.
Colombia's Alejandro Falla saved six set points in the second set to post a 7-6 (10/1), 7-6 (12/10) victory over Flavio Cipolla in the first round of the ATP Tour's SAP Open on Wednesday.
Juan Martin del Potro overcame a first set back problem to make a winning start at the Swiss Indoors on Wednesday with a 6-4, 6-1 defeat of Alejandro Falla.
World number six Tomas Berdych reached the quarter finals of the Japan Open on Thursday after beating Colombia's Alejandro Falla in a straightforward 6-3, 7-5 win.
Nikolay Davydenko beat lucky loser Sanam Singh of India 7-5, 6-4 Wednesday in the first round of the Malaysian Open.