Frenchman Fils overpowered Russia's Andrey Rublev 6-2 7-6 (7-2) to lift the Barcelona Open crown on Sunday, while American world No.6 Shelton defeated Italian Flavio Cobolli 6-2 7-5 to take victory in the Munich Open.
In Spain, it was the fourth ATP title and third on clay for 21-year-old Fils, who's looking good, having returned from a nearly eight-month injury lay-off in February.
Fils took the first set in just 31 minutes, winning seven games straight before Rublev managed to hold his own serve to make it 1-1 in the second.
The 28-year-old fended off seven break points to prevail in a 13-minute battle to stay even at 2-2, but Fils outwitted Rublev with a backhand drop shot to get a decisive break and go 4-2 up.
Fils, 5-3 up and serving for the tournament, made three straight errors to hand Rublev a break back and the Russian saved three match points to hold his serve and make it 5-5, before breaking Fils to go 6-5 up.
Yet the Frenchman hit straight back and went on to prevail in the tiebreak to ensure that he'll be back in the world's top 25 this week.
In Germany, Shelton also showed why he could be a force to be reckoned with at next month's French Open as he claimed his fifth ATP crown with a convincing win over Cobolli, who had beaten home favourite Alexander Zverev in the semis.
"I came out at a really high level and have done that before against him," Shelton said in his on-court interview. "The toughest thing is maintaining it as he raises his level. I managed to do that in the second set and played some great tennis.
"I'm happy with my performance this week. I got better and better as the week went on and I'm happy with the work me and the team put in."
