PHOTOS: Serena joins in Wimbledon drills from afar

Even Serena Williams was getting in the Wimbledon groove on Monday - and she was nowhere near the London grass courts.

As the first day's play got under way, she posted a video clip on Instagram of her pounding backhands on a clay court despite being absent from the tour since winning the Australian Open in January as she is expecting her first child.

"Wimbledon got me like: Easy standing drills this morning. Go easy," the 2016 champion posted to her 6.1 million followers.

Her coach Patrick Mouratoglou told Reuters at the French Open last month that the 23-times grand slam champion was still hitting and working out to keep her touch.

Even though she has been out of action for nearly six months, she has also still been making the tennis headlines.

Last week, she took to Twitter to ask John McEnroe for "respect" after the seven-times grand slam champion said his fellow American would be ranked "like 700 in the world" if she had to play on the men's circuit.

Serena not being at from the grass court major is clearly a loss for some fans.

"I'm not even watching women's Wimbledon without you. I just won't be able to. Awaiting your comeback," one, identified as queendeebs, replied to the Instagram posting.

For world number two Simona Halep, Serena's absence is, however, becoming normal.

"We didn't see Serena since the Australian Open... I'm not thinking about Serena when I go to the tournament now because she's missed, like, five, six months already," the Romanian told reporters after her first round win.

But for Venus Williams, the absence of her younger sister and doubles partner from the All England Club is acute.

"I miss her a lot. I think she misses me," she told reporters.