Iga Swiatek and Carlos Alcaraz won in straight sets to retain their titles in Stuttgart and Barcelona respectively.
Polish world number one Iga Swiatek beat world number two Aryna Sabalenka of Belarus 6-3 6-4 in a repeat of last year’s final.
In Spain, Alcaraz breezed past Stefanos Tsitsipas of Greece 6-3 6-4 to win the tournament without dropping a set.
It was a third title of the season for the 19-year-old Spaniard, following wins in Buenos Aires and Indian Wells.
Both Swiatek and Alcaraz have been suffering from injury in recent weeks but have returned to fitness and form as they build up to the French Open at Roland Garros next month, where the Pole will be defending her title.
Swiatek was playing her first tournament since recovering from a rib injury that forced her to miss the Billie Jean King Cup qualifiers and Miami Open.
She is the first player to win back-to-back Stuttgart titles since Angelique Kerber in 2015 and 2016, with Sabalenka suffering her third successive defeat in the final.
It was the first time a women’s world number one had faced the number two on clay since Serena Williams beat Maria Sharapova in the 2013 French Open final.
Alcaraz, meanwhile, appeared so show no ill-effects from the hand and back problems that forced him to miss the Monte Carlo Masters last week.
With 14-time French Open champion Rafael Nadal out since January with a hip injury and world number one Novak Djokovic struggling with an elbow problem, Alcaraz will be among the key contenders when the tournament in Paris begins on 28 May.
In the men’s doubles final in Barcelona, Great Britain’s Neal Skupski and Dutch partner Wesley Koolhof were beaten by Argentine pair Maximo Gonzalez and Andres Molteni.
Gonzalez and Molteni won 4-6 7-6 (10-8) 10-4 to claim their third title of the year after victories in Cordoba and Rio de Janeiro.
In Germany, Denmark’s Holger Rune produced a remarkable comeback in a thrilling final set to overcome Dutchman Botic van de Zandschulp and defend his BMW Open title.
Rune, struggling with a upper arm injury, was seemingly on the brink of defeat at 2-5 15-40 down on the Van de Zandschulp serve.
The 19-year-old then twisted his ankle in the 10th game but still managed to save four championship points and force a tie-break, which he won to seal a 6-4 1-6 7-6 (7-3) victory.
It was Rune’s fourth ATP title and a repeat of the 2022 final, which saw Van de Zandschulp retire injured after just seven games of the first set.
In Bosnia-Herzegovina, Dusan Lajovic won the Srpska Open with a three-set win over world number six Andrey Rublev.
The Serb world number 70, who beat Novak Djokovic in the quarter-finals, won 6-3 4-6 6-4 to claim just his second career title.
“Honestly it was probably the toughest match I have had in the past six months. I felt drained,” said the 32-year-old, whose first title was the Croatia Open in 2019.
“The last time I was in a final was four years ago and I have been through a lot since then, lots of ups and downs.
“But on the other side I still believed in myself, even though I did not have the best last year. This victory means a lot.”