Kenin, who won the Australian Open as a 21-year-old in 2020, recovered from a second-set lapse to outlast Ruse and set up a second-round clash against seventh seed Ekaterina Alexandrova.

“My last match was in October so it was definitely weird. But I trusted the pre-season I had and I felt like I was playing good tennis,” said the 27-year-old American.

“She is a really tough player and I had to stay with it, definitely wasn’t easy,” she added.

Australian wildcard Ajla Tomljanovic eased into the second round with a 6-1, 6-3 win over France’s Elsa Jacquemot and will now play 11th seed Karolina Muchova.

“I had such a great preparation but you never know when that first match comes, anything can happen on the day,” Tomljanovic said.

“I was hoping to do at least 80 percent of what I’ve been practising and I think I did even more. This feels amazing,” Tomljanovic added.

In the men’s draw, American Francis Tiafoe was too strong for Australian wildcard Aleksandar Vukic 6-2, 6-2.