Melbourne, Australia (SportsNetwork.com) - Serena Williams quest for an 18th career singles Grand Slam title will have to wait a few more months. The world No. 1 will have to start a new winning streak too. Serbian Ana Ivanovic stunned Williams, 4-6, 6-3, 6-3 Sunday to reach the quarterfinals of the Australian Open. The 14th-seeded Ivanovic ended Williams 25-match winning streak and dealt the American a shocking fourth-round exit. Ivanovic, who was the runner-up in Melbourne in 2008 and was the French Open champion later that year, took advantage of 31 unforced errors from Williams. "Its not easy playing such a champion and Ive never beaten her before," Ivanovic said during an on-court postmatch interview. Before this match, Ivanovic had lost all four previous matchups against Williams. In fact, she hadnt taken a set against her, but that all changed at Rod Laver Arena. A five-time Australian Open champion, Williams lost for just the second time in 53 matches at the event when winning the first set. Her only previous defeat came last year in the quarterfinals to Sloane Stephens. Williams fought back from a break down to win the first set, but in the second Ivanovic broke for a 3-2 edge. She finally finished off the set on her third chance, a forehand winner. "I had some confidence coming into todays match," Ivanovic said. "I really did certain things extremely well, you know, and I kept her under pressure I felt throughout the whole match." The errors then started to pile up for Williams, as she lost the first three games of the final set. Williams held serve to get within 5-3 and saved one match point when Ivanovic sent a forehand into the net. The encounter finally ended when Williams sent a return long. "I wasnt the best, but it was all Anas day. I thought she played really well," said Williams, who fired 13 aces. "I made a tremendous amount of errors. Im just not used to missing those shots." Williams has been dealing with a back injury, which she termed as not "life threatening" but said she was unable to get additional days off due to the schedule of playing essentially every other day as a Grand Slam tournament requires. She even contemplated not taking the court Sunday due to the injury, but gave Ivanovic all the credit for winning. "I think its almost good I lost today because now I know what I have to work on," added Williams, who pulled out of the doubles competition with her sister, Venus before their first-round match. That was because Venus had a lower left leg injury. Ivanovic will face either 30th seeded Canadian Eugenie Bouchard or Australian Casey Dellacqua in the quarterfinals. Only three players have won 18 Grand Slam singles titles in the Open Era - Chris Evert (18), Martina Navratilova (18) and Steffi Graf (22). Serenas next chance at No. 18 will come at the French Open at the end of May. Fourth seed Li Na of China bested 22nd-seeded Russian Ekaterina Makarova, 6-2, 6-0 in 59 minutes. Li, who lost to Victoria Azarenka in last years finale in Melbourne, will face Italian Flavia Pennetta in the quarterfinals. The 28th-seeded Pennetta, who did not play the 2013 Australian Open due to a wrist injury. upended No. 9 seed Angelique Kerber of Germany, 6-1, 4-6, 7-5. This is Pennettas first quarterfinal appearance at the Aussie Open, but her second straight such showing in a Grand Slam tournament. Pennetta, who fired eight aces, was ousted by Azarenka at the 2013 US Open semifinals. Since 1999, only one German player has advanced to the Australian Open quarterfinals. That was Andrea Petkovic in 2011. Cheap Soccer Jerseys . His team rose to the occasion Sunday with a 3-1 victory over Sweden in the bronze-medal game. "The sting from yesterday is not something we hid from or pretend didnt happen," Dineen said. Wholesale Soccer Jerseys . Bale has had a successful debut season in Spain, and Ancelotti appears ready to reward him with a starting role on Saturday. Ancelotti says "Gareth had some problems at the beginning (of the season) but when he found good physical condition he scored a lot of goals, he had a good impact on the team. https://www.soccerjerseyschina.us/ . - Free agent defensive end Will Smith has signed with the New England Patriots. Wholesale Soccer Jerseys China .com) - Minnesota Vikings running back Adrian Peterson lost an appeal to have his indefinite suspension overturned, the NFL announced Friday. Replica Soccer Jerseys . Inter Milan ended its five-match winless streak in all competitions by beating 10-man Bologna 3-1 on new manager Claudio Ranieris debut, while injury-plagued AC Milan edged Cesena 1-0 with an early goal from Clarence Seedorf. LUXEMBOURG -- Top-seeded Caroline Wozniacki beat two-time finalist Monica Niculescu of Romania 6-3, 6-2 to reach the quarterfinals of the Luxembourg Open on Thursday. Wozniacki joined second-seeded Sloane Stephens of the United States, who advanced by beating Yvonne Meusburger of Austria 7-5, 6-4. Sabine Lisicki made it a perfect day for the top three seeds when the German defeated Teereza Smitkova of the Czech Republic 6-4, 6-0.dddddddddddd Stephens, ranked 12th in the world, has yet to lose a set in Luxembourg and will play Stefanie Voegele on Friday. The 54th-ranked Swiss player struggled to beat Karolina Pliskova of the Czech Republic 6-1, 3-6, 6-3. In another second-round match, Karin Knapp of Italy beat Andrea Petkovic of Germany 7-5, 7-5. ' ' '