Kirilenko, the No.10 seed at the Premier-level tournament, showed some rust early on - she fell behind 61 52 against Swiss qualifier Belinda Bencic, and quickly found herself down triple match point in that game too serving 0-40. But that's when Kirilenko started showing flashes of her former brilliance - she fought off all three of those match points, a fourth match point later in that same game, and then another two in the next game when Bencic held double match point leading 40-15 on her serve.
After clawing back to 5-all Kirilenko even brought up break points in the next game, but Bencic fought them off then broke one more time to close out the 82-minute second set and the match, 61 75.
"The first match back is always tough, but I thought it was going to be worse today. I don't think I looked too bad," Kirilenko said. "It was difficult to keep going all two sets, because from time to time I felt like I was getting too tired, and my legs were getting very tired because of the clay.
"But it felt good to be back, for sure."
"I'm so happy to be back on clay - I love it," Keys said. "I didn't play great at times, and well at other times - it was just one of those first matches back on clay. I'm just happy to get through it."
Keys talked about the difficulties of transitioning from hardcourts to clay courts this week.
"You definitely have to change your game, like obviously if I'm 10 feet behind the baseline I can't go for a winner, because it slows the ball down," she said. "I can slide, which is the good thing, but I'm still trying to work on some stuff. At the same time I'm trying not to overthink everything right now."
Other winners on Day 1 were Elina Svitolina, Yaroslava Shvedova, Lauren Davis, Ajla Tomljanovic, Chanelle Scheepers, Jana Cepelova, Virginie Razzano, Petra Cetkovska, Teliana Pereira and qualifiers Alla Kudryavtseva, Kiki Bertens and Grace Min. Tomljanovic had the fiercest battle of the day, rallying from 5-2 down in the third set - and saving match point down 5-4 - to beat Stefanie Voegele.