Milos Raonic was unable to celebrate his return to the ATP World Tour with a title as Marin Cilic pipped him to the Istanbul Open crown in Turkey.
Raonic had played only one match since February prior to arriving in Istanbul because of a hamstring problem but found form straight away on the clay.
However, it was Cilic who proved just the stronger in the title decider, winning the opening set on a tie-break and then securing the only break of serve in the second to triumph 7-6 (7/3) 6-3.
Raonic had his chances, creating seven break points in the match, but Cilic saved all of them, helped by nine aces.
Cilic said: "I'm on a good track and feeling very well. In these last three or four weeks on clay, it's never easy, but I'm trying to get better with every match.
"This week was a big one for me and a good sign for the rest of the claycourt season. I hope I can improve in these upcoming three tournaments - two Masters 1000 events (Madrid and Rome) and the French Open."
The beaten Raonic was upbeat following his comeback event.
"The tennis was good and I achieved a lot of the things I would have liked," he said. "Of course I didn't achieve the ultimate thing, but I got a much better understanding of how I need to play on clay and I got to play four matches."
At the BMW Open in Munich, 20-year-old Alexander Zverev won his third ATP title and his first on home soil.
The German, ranked 20th, came from a break down in the opening set to defeat Argentinian qualifier Guido Pella 6-4 6-3.
Success in from a home crowd meant a lot to Zverev, who said: "I lost the final in Halle last year (to Florian Mayer), which was very painful. I really wanted to win a tournament in Germany, which I've done now and I'm very happy about it.
(It's) obviously my first title on clay as well. It's a great feeling right now.
“I'm confident. I'm playing well so hopefully I can keep going and play some great tennis in the upcoming weeks.”
Pablo Carreno Busta did not drop set on his way to collecting the Estoril Open title in Portugal.
The Spaniard had a tricky draw pitting him against Tommy Robredo, Nicolas Almagro and David Ferrer but proved stronger than all of them before seeing off Luxembourg's Gilles Muller 6-2 7-6 (7/5) in the final.
The men's main draw action also got under way at the fourth Masters 1000 tournament of the season in Madrid.
Ninth seed David Goffin booked his place in round two with a 6-2 7-6 (10/8) victory over rising young Russian Karen Khachanov while Fabio Fognini defeated Joao Sousa 6-4 6-4 to set up a clash with tournament favourite Rafael Nadal.
