London, United Kingdom: Serena Williams hailed Novak Djokovic for making "extreme history" despite her fellow number one having suffered his earliest Grand Slam exit in seven years.
Two-time defending champion Djokovic suffered a shock defeat to the unheralded Sam Querrey of the United States in the Wimbledon third round on Saturday.
It ended his hopes of going on to secure the first calendar Grand Slam since Rod Laver in 1969.
But Williams, the women's world number one and chasing an Open era record 22nd Grand Slam title, saluted Djokovic, who had won the last four Slams in a row.
"He and I have both made extreme history. He's won four in a row. I won four in a row last year. I think that's historic in itself," said Williams, who is chasing a seventh Wimbledon title this year.
"I am in those situations. Every time I step out on the court, if I don't win, it's major national news. But if I do win, it's just like a small tag in the corner."
Laver questions Djokovic motivation
Meanwhile, Laver admitted he was saddened by Djokovic's failure to break his 47-year long Grand Slam record.
"I'm still happy to have the title, but I don't own it," Australian legend Laver told ESPN television.
"I would have liked to have been at the US Open and be the first to shake Djokovic's hand if he did it. Don Budge did that for me in 1962 at Forest Hills."
US player Budge won the first calendar Grand Slam in 1938 before Laver achieved the feat twice, in 1962 and 1969.
Budge's message to Laver was: "Welcome to an exclusive club."
Djokovic had already captured the Australian and French Open titles in 2016 and was heavily favoured to defend his Wimbledon crown.
That would have left just the defence of his US Open trophy standing in the way of him and a place in the record books.
Laver, 77, believes Djokovic may have been lacking motivation after finally winning a first French Open last month which gave him ownership of all four Slams at the same time.
"He just wasn't himself. Something was off," said Laver.
"Maybe he felt winning all four titles and being the defending champion of all four was a Grand Slam in his mind.
"And so even if it wasn't in the calendar year, it didn't matter. Way back in there somewhere you are thinking one thing, that it doesn't matter, but you are thinking it does matter.
"Those are two different thoughts to have when you are playing."
Djokovic looking for positives
Djokovic had admitted that he hadn't been "100 percent healthy" in the match with Querrey and was spotted rubbing his left shoulder as the tie slipped away.
But the 29-year-old refused to dwell on failing to grab Laver's record.
"I managed to win four Grand Slams in a row. I want to try to focus on that rather than on failure," the Serb said.
"Coming into Wimbledon, I knew that mentally it's not going to be easy to kind of remotivate myself."
World number two Andy Murray, the 2013 Wimbledon champion, said Sunday that Djokovic's defeat would have little bearing on his preparations.
As the top two seeds, they were scheduled to meet in the final and not before.
"The players left in my section of the draw are still formidable," Murray told the BBC.
"You've got Nick Kyrgios (who he plays in the last 16), who's beaten Rafa on Centre Court; Tsonga is one of the best grass-court players in the world; Richard Gasquet's still in there and he made the semis last year."
"There are some pretty decent players left in my way, so I'm not getting carried away."