Victoria Azarenka and Serena Williams both suffered scares before securing their places in the second round of the Australian Open.
Tournament favourite Williams was not troubled in the slightest by opponent Edina Gallovits-Hall, winning 6-0 6-0, but by a right ankle injury which required lengthy treatment after a heavy fall on Hisense Arena.
Azarenka, the top seed, was given a tougher-than-expected ride by Monica Niculescu before coming through 6-1 6-4 after a second-set wobble.
It was her first appearance on RLA since her thrashing of Maria Sharapova in last year's final and Azarenka admitted she was pleased to have avoided an embarrassing return.
"It's great to be back, there were a lot of overwhelming emotions out there," she said. "I started really well but the second set was a struggle. I am pleased to get through."
Former world number Caroline Wozniacki also progressed but only after a wonderful deciding-set comeback against Sabine Lisicki. Lisicki led 3-0 in the third only to run out of steam as 10th seed Wozniacki hit back to clinch a morale-boosting 2-6 6-3 6-3 triumph.
Eighth seed Petra Kvitova overcame Francesca Schiavone in three sets in a battle of former grand slam champions, 14th seed Maria Kirilenko ousted Vania King and 16th seed Roberta Vinci overcame Silvia Soler-Espinosa.
There were a couple of shocks, though, with seventh seed Sara Errani, a quarter-finalist here last year, and 12th seed Nadia Petrova both going out in the first round. Errani was beaten 6-4 6-4 by Spain's Carla Suarez Navarro while Petrova was thrashed 6-2 6-0 by Japanese veteran Kimiko-Date Krumm.
At 42, Date-Krumm became the oldest winner of a women's singles match in the tournament's history.
"I'm very happy to win today, but I don't play for the records," she said. "Even when I lose, I still enjoy it. Of course, every time I lose...it's tough. But still I enjoy playing. I love tennis. I like practice. I like games. I like the tour. I enjoy it a lot."