LONDON, Great Britain - Former World No.1 Serena Williams returned to Wimbledon for the first time since tying Stefanie Graf's Open Era Grand Slam record back in 2016, knocking out dangerous Dutch veteran Arantxa Rus, 7-5, 6-3 on No.1 Court.

"More than anything, I just was trying to be more calm," she said during her post-match press conference. "I wanted to do so well. Sometimes that works against you sometimes. I feel like I was just overly anxious and overdoing it. Towards the end, I definitely was more calm, just making my shots, just playing a more serene game. I feel like it worked out."

The American followed up that historic win with a record-breaking trimph at the 2017 Australian Open to own the Open Era record, but missed the next four major tournaments as she married and gave birth to daughter Alexis Olympia Jr. She returned to tennis at the BNP Paribas Open back in March and made her major return at Roland Garros in May.

"It’s a great feeling. It’s been a couple of years since I played on grass. It’s definitely different, so I’m trying to find my bearings out there."

Seeded No.25 at the discretion of the All England Club, Williams showed flashes of brilliance and plenty of fight through the one hour and 28 minute match as she and Rus treated the crowd to two tense sets that culminated in a titanic final game, which she won on her sixth match point.

"I haven't played a tremendous amount of tennis since I had the baby, and I haven't played in wind in a really long time. So I'm just not used to that yet.

"It was really windy for me today. I just wasn't quite used to that level of wind. Something that I would normally be okay with, normally have, 'Oh, this is this.' It's just getting all back to the hang of things, getting used to different circumstances. At the time I wasn't happy, but looking back, I'm glad I had that win. In the future I'll be able to play a little bit better."

Rus was looking for her first major main draw victory since 2012, when she pulled off one of her two signature upsets over then-World No.5 and reigning US Open champion Samantha Stosur. A year earlier, she rallied from the brink of defeat to end Kim Clijsters' 15-match winning streak at Roland Garros.

"She played unbelievably today. I’ve never seen her play like that, but that’s the game. You have to be ready for everything. I’m happy to get through because I didn’t play my best. I’ll get there; I’ll take it one match at a time."

Some of that big-match experience was on display as the 27-year-old recovered from an early break down in the first set and led Williams 3-1 in the second set before the American flipped the script in fine fashion, winning the final five games of the match to book a second round clash with Viktoria Tomova, who outlasted wildcard Tereza Smitkova in straight sets.

"In the moment you want to do so well, you want to win. I have such high expectations of myself. I expect to go out there. I expected to win this match. I don't go out there expecting to do well, see what happens.

"That's just not me: not only do I expect to win, I expect to win emphatically. Sometimes, I put too much pressure on myself, I'm overanxious. It's really just about learning that balance for me still."