(CNN) -- The seeds just can't stop tumbling out of Wimbledon and on Monday it was the turn of world No.1 and five-time champion Serena Williams to experience that sinking feeling.
The American crashed out of the grass court grand slam in the last-16 following a shock defeat by Germany's Sabine Lisicki -- her first reverse in 35 matches.
Favorite for the title, Williams lost the opening set 6-2 before roaring back to level a pulsating contest by taking the second 6-1.
But Lisicki, seeded 23rd at the tournament, produced one of the greatest performances of her career, coming from a break down to take the final set 6-4 and send shockwaves through tennis.
After knocking out the defending champion, the 23-year-old German burst into tears of joy when addressing the media for the first time.
"I am still shaking, I am so happy," she told the BBC.
"Serena played a fantastic match, she is such a tough opponent. It is an amazing feeling to win this match.
"This is such a special place for me and the crowd were brilliant to me. I gave it everything I had, I fought for every single point to try to win it somehow."
A Wimbledon semifinalist in 2011, Lisicki will play Estonia's Kaia Kanepi for a place in the last four.
The German has never gone past the fourth round at any grand slam outside of Wimbledon but she has an impressive record at The All England Club, having reached the quarterfinals three times, and a curious one as well.
For she has beaten the reigning French Open champion at all four of her last Wimbledon championships.
Since she missed the 2010 edition through injury, the run starts in 2009 when she beat Svetlana Kuznetsova, a success that has now been followed by defeats of Li Na in 2011, Maria Sharapova the following year and Williams herself on Monday.
In a tournament packed with shocks, the dethroning of 16-time grand slam winner Williams is arguably the greatest of all -- despite the defeats for Rafael Nadal and Roger Federer in the opening rounds last week.
The win was all the more surprising given that the powerful American bounced back so strongly from losing the first set that she won nine consecutive games on the way to taking a 3-0 lead in the deciding set.
But Lisicki broke back and even though Serena responded in similar style, the German once again overcame the American's serve to level the set at 4-4.
After the match had gone past the two-hour mark, Lisicki earned her first match point and after that went begging she made no mistake for the second to claim surely her greatest win to date.
Williams' remarkable twelve months - a spell where she won the Wimbledon, U.S. Open, French Open and Olympic titles - was finally at an end however and she was quick to praise her opponent.
"It's not a shock," the 31-year-old said. "She plays really good on grass. For me any loss is extremely tough to overcome. I just have to go back to the drawing board and figure out a way to win those matches."
The last time Williams lost a match on court was when she was beaten in the final of the Qatar Open by Victoria Azarenka on 17 February.
Lisicki will face Kaia Kanepi after the Estonian ended Laura Robson's dream of becoming the first Briton to reach the quarterfinals at Wimbledon in 29 years.
The 19-year-old was the first British woman to reach the second week at Wimbledon since 1998 but left the court in tears after being beaten 7-6 7-5.
Should Kanepi reach her first grand slam semifinal, she will meet either Agnieszka Radwanska, last year's runner-up, or Li Na in the semifinals.
The fourth seed from Poland overcame Bulgaria's Tsvetana Pironkova 4-6 6-3 6-3 while the Chinese sixth seed demolished Italian 11th seed Roberta Vinci 6-2 6-0 in just 55 minutes.
Looking to win her second grand slam after her Roland Garros title two years ago, Li has reached the quarterfinals for the third time at Wimbledon and is seeking her maiden semifinal appearance.
Few would have predicted that Sloane Stephens would be the last American left standing in both singles draws but after her 4-6 7-5 6-1 defeat of Puerto Rican youngster Monica Puig, the 20-year-old is through to the Wimbledon quarterfinals for the first time.
The 17th seed will meet the 15th seed after Marion Bartoli, the beaten finalist in 2007, defeated Italy's Karin Knapp in straight sets.
In the remaining quarterfinal, 2011 Wimbledon winner Petra Kvitova will face Belgium's Kirsten Flipkens.