World number one Alcaraz has at times struggled with precision and a lack of consistency in his serving technique and has mixed it up for the opening Grand Slam of the year.

Eagled-eyed fans noticed that his more compact action now bears a striking resemblance to Djokovic, who was asked about it after coasting into the second round at Melbourne Park.

"As soon as I saw it, I sent him a message. I said, 'we have to speak about the copyrights'," the 24-time major winner joked.

"Then when I saw him here, I told him we have to talk about a percentage of his winnings.

"Every ace I expect, you know, a tribute to me. Every ace that he makes here. Let's see if he's going to stick to the agreement."

Asked about his new serve ahead of the tournament, Alcaraz said he was flattered by the comparison to Djokovic, he insisted it was a coincidence.

"No. I didn't think about, or I wasn't thinking about making the same serve as Djokovic," he told reporters. "But at the end, I can even see the similarities."