The third Grand Slam of the season kicked off at the All England Club on Monday. In what has become a familiar trend, there were several surprises at Wimbledon. Here are some of the Day 1 highlights from the women’s draw.

Azarenka Victorious in Return

Victoria Azarenka returned to the big stage after an injury that forced her to the sidelines for the majority of the year thus far. It was a successful result as the former world No. 1 defeated Mirjana Lucic-Baroni 6-3 7-5. It is Azarenka's first victory since a quarterfinal run at the Australian Open. She came back to action at a Wimbledon warm-up at Eastbourne last week but lost her only match there. Azarenka had not seen action before then since Indian Wells in March.

“I'm just very happy to be able to play. This is what I love to do. The best feeling is to play pain-free,” she said. Wimbledon has not been friendly to Azarenka recently, since she twisted her knee in the first round at last year's tournament. The injury eventually forced her out of the competition.

Azarenka struggled with her serve, tossing in eight double faults. Nonetheless, the No. 8 seed advanced and will face Bojana Jovanovski in the second round.

Early Upsets on Day 1

The 17th seed Sam Stosur and 18th seed Sloane Stephens fell in straight sets on Monday, headlining early upsets at the All England Club.

Stephens, who generally plays her best at the Grand Slams, exited at the hands of Maria Kirilenko 6-2 7-6. Battling back late in the match, she staved off five match points in the second set before forcing a tiebreak. There, Stephens failed to capitalize on two set points and fell in straight sets.

Stephens had received a difficult opening assignment, facing an opponent who was in the top 10 a year ago. Injury struggles have sent the Russian into a slide, where she is presently ranked No. 109. But Kirilenko showed signs of her previous form with solid ball-striking on Monday.

Meanwhile, on a surface that does not tend to suit her, Sam Stosur fell to Yanina Wickmayer 6-3 6-4 on day one. The Belgian took advantage of errors off the Australian's racket early and cruised to the first set in 31 minutes. However, Stosur did show fight late in the second set. She broke Wickmayer when her opponent served for the match at 5-3. But that success was quickly dampened as the 30-year-old could not consolidate her break, losing in straight sets.

The result frustrated Stosur. “I’m pretty annoyed about it, to be honest. I don't have an answer because I do feel I played well. I think she played well, and she stuck to it right from the first point to the last point.”

No Cinderella Story for Muguruza in London

Just a few weeks prior, Garbine Muguruza turned the tennis world upside down when she dismantled Serena Williams at Roland Garros. But her stay in London was a quick one as she fell to CoCo Vandeweghe of the United States, 6-3 3-6 7-5.

Vandeweghe, still riding momentum from her Dutch Open title last week, took advantage of the Spaniard’s struggles most of the day. It was the American's first career win at Wimbledon. It took 13 match points, but the 22-year-old finally closed the deal with a similar result against Muguruza as the pair's match from the Netherlands last week. With the victory, Vandeweghe runs her streak to eight consecutive wins on the grass.

Having defeated Muguruza for the second time in a week, Vandeweghe reflected, “The toughest part for me was that I played her the week before. I knew she would come out even more fired up because of the recent memory of her loss.”

The California native improved her ranking to No. 51 after her title last week, which is the best of her career. She will move on to face Tereza Smitkova in the second round.

Venus Williams Fights off Upset Bid

Venus Williams jumped out to a fast start but had to fight to an avoid upset, defeating María Teresa Torró-Flor 6-4 4-6 6-2 on Monday. The win was the 72nd of her career at Wimbledon, good for fourth-best behind just Martina Navratalova, Chris Evert, and Steffi Graf at the venue.

The five-time Wimbledon Champion still has her sights set on major championships, despite her age of 34 and battle with Sjögren’s syndrome. When asked how many Wimbledon championships she owns, Venus responded, “Not enough.” She advances to face Kurumi Nara of Japan next.