IN Paris, it was the guttural roar. At Wimbledon, it was a thunderous 'C'mon'.

On both occasions, the message was the same - Serena Williams was trailing in a grand slam match, but she had no intention of losing.

Against Ash Barty at the French Open and Camila Giorgi at the All England Club, Williams again illustrated why she is so accomplished. And tough.

"It's weird. Sometimes I feel 'Man, I'm in trouble'," she said after staving off Giorgi.

"Sometimes I feel, I can fight. For whatever reason, today I was so calm.

"Even when I was down the first set, I thought 'Well, she's playing great. I'm doing a lot of the right things. It is what it is'."

Tested, Williams does what she mostly always does. She found another gear to shrug off Giorgi 3-6 6-3 6-4.

Even with the publicity around the birth of her daughter Alexis last year, it is occasionally overlooked that this is only the fourth tournament Williams has played in 18 months.

And she is back in the semi-finals of a major, and on the cusp of grand slam history.

Can anyone stop Serena at Wimbledon? Picture: AP.
Can anyone stop Serena at Wimbledon? Picture: AP.

If she wins two more matches, she will lift an eighth Wimbledon trophy and equal Margaret Court's all-time record of 24 slams.

She would also become the first mother to win here since Evonne Goolagong in 1980.

Even Williams, 36, is surprised.

"I think everything right now is a little bit of a surprise," she said.

"To be here, to be in the semi-finals. I mean, I always say I plan on it, I would like to be there, have these goals.

"But when it actually happens, it still is, like, 'Wow, this is really happening'."

Camila Giorgi had her chance but Serena rallied to win. Picture: AP.
Camila Giorgi had her chance but Serena rallied to win. Picture: AP.

Williams has built a career of boisterously staring down challenges and challengers.

In the Giorgi match - apart from her explosion after winning the second set - she was much calmer.

The warrior in Williams knows it won't last. Not with history on the line.

"Just to be clear, that (calmness) was just today. I mean, I'm hoping this is like a new thing," she said.

"Honestly, I highly doubt it. It was just the way I felt today. I never felt it was out of my hands.

"It's weird. I can't describe it. I just felt calm. Hoping I can channel that all the time, but one day at a time."

Williams will play German Julia Goerges in the semis for the right to face either Angelique Kerber or Jelena Ostapenko in Saturday's decider.