Tennis great Billie Jean King hailed Serena Williams for possessing "the most beautiful serve ever" after the world number one defeated Angelique Kerber to retain her Wimbledon singles crown.

Williams' serving prowess ultimately proved key in a high-quality final, the American firing 13 aces on her way to a 7-5 6-3 victory on Centre Court.

In securing her seventh Wimbledon title, Williams - who had been beaten earlier this year in the finals of the Australian and French Opens - drew level with Steffi Graf as the most prolific female winner of grand slam singles titles in the Open Era.

Both Graf and Williams now hold 22 titles, two shy of Margaret Court's overall record tally.

King reserved particular praise for Serena's most potent weapon on Saturday, telling BBC Sport: "That was the big difference, because on groundstrokes I think they [Williams and Kerber] match up very well.

"Kerber only had one break point, and what does Serena do, come up with two aces in a row.

"It is the most beautiful serve ever and I always tell young people to watch Serena, [Pete] Sampras and, we're going to go way back, Pancho Gonzales. Those three, just make a loop of them and keep watching them over and over.

"I remember seeing Serena when she was very young, probably 12, and I went 'whoa'. Her technique already was just beautiful. She just felt it naturally. She just stays so connected on it, everything stays connected. It's just beautiful, she is such a terrific athlete."

King believes Williams is capable of surpassing Court's haul of 24 slam crowns and added: "If she just can keep her motivation and stay healthy, maybe she'll be our greatest ever. I think she should be, I think she is, but she still has to prove it.

"I find the very top players hate to lose more than they like to win. Serena hates losing. She absolutely goes crazy. I always talk about the head, the heart and the guts have to be together to make greatness, and that's what Serena has.

"You can find a lot of terrific physical athletes, you really can. You can find tonnes. But if they don't have it emotionally and mentally, they're not going to make it."