Sharapova withdrew from the 2012 Brisbane International because of her ongoing ankle injury. Her first tournament of the season was the 2012 Australian Open, where she was seeded fourth. Sharapova advanced to the fourth round conceding just five games, defeating Gisela Dulko, Jamie Hampton, and the 30th seed Angelique Kerber en route. In the fourth round, Sharapova defeated the fourteenth seed Sabine Lisicki in three sets, 3–6, 6–2, 6–3, to reach her first hardcourt Grand Slam quarterfinal in four years. She then defeated compatriot Ekaterina Makarova in straight sets, 6–2, 6–3, to reach the semifinals.
There she defeated the world No. 2 Petra Kvitová, 6–2, 3–6, 6–4, to reach her third Australian Open final, and her sixth grand slam singles final overall. She lost to Victoria Azarenka in the final 3–6, 0–6. As a result her ranking improved to world No. 3.
In February, Sharapova aided Russia to a 3–2 victory over Spain during the 2012 Fed Cup quarterfinal with a 6–2, 6–1 win over Silvia Soler-Espinosa.
She then played in the Paris, where she lost in the quarterfinal to eventual champion Angelique Kerber 4–6, 4–6. As a result her ranking improved to World No. 2.
At the Indian Wells, Sharapova faced Gisela Dulko in the first round and won 6–2, 6–0. Sharapova defeated Simona Halep and Roberta Vinci en route to reaching the quarterfinals. After battling for over three hours, she defeated compatriot Maria Kirilenko, 3–6 7–5 6–2, to set up a semifinal meeting with Ana Ivanovic. Sharapova won the first set 6–4 and advanced to the final after Ivanovic retired due to a hip injury. In the final, she played world No. 1 Victoria Azarenka in a rematch of the Australian Open final, but lost again 2–6, 3–6.
Sharapova's next tournament was the 2012 Sony Ericsson Open, where she was seeded 2nd. She received a bye to the second round where she faced Shahar Peer and won in three sets 4–6, 6–3, 6–3. Her next opponent was Sloane Stephens, where Sharapova won in straight sets 6–4, 6–2. In the fourth round she won in straight sets, 6–4, 7–6, against countrywoman Ekaterina Makarova and advanced to the quarterfinals where she faced Li Na, whom she beat 6–3, 6–0. Her semifinal opponent was fellow former world No. 1 Caroline Wozniacki.
After an inconsistent first set, Sharapova won the match 4–6, 6–2, 6–4. In the final, Sharapova lost in straight sets to 5th seeded Agnieszka Radwanska 7–5, 6–4. This was her third loss of the year in finals out of four tournaments played so far.
In the Porsche Tennis Grand Prix in Stuttgart, Sharapova was seeded second. She had a bye in the first round, and advanced to the third round after Alize Cornet retired in the second set. In the quarterfinal, she defeated No. 5 Samantha Stosur 6–7(5), 7–6(5), 7–5 after saving a match point in the second set, and advanced to the final with a 6–4, 7–6(3) win over No. 3 Petra Kvitova. She won her first title of the year in Stuttgart after defeating world number one Victoria Azarenka 6–1, 6–4. In doing so, Sharapova defeated three current Grand Slam title holders to win the tournament. It was also her first win against Victoria Azarenka in five finals, and the third of such this season.
Sharapova then played on the controversial blue clay courts of the 2012 Mutua Madrid Open, a premier mandatory event. She eased through the first round in straight sets against Irina-Camelia Begu 6–0, 6–3. In the next round she faced Klara Zakopalova and also won in straight sets with 6–4, 6–3. In the third round Sharapova's opponent Lucie Safarova was unable to compete and withdrew from the tournament, earning Sharapova a walkover into the quarterfinals. She was then beaten by eventual champion Serena Williams in straight sets 6–1, 6–3.
Sharapova carried the flag for Russia during the Opening ceremony of the 2012 Summer Olympics. She lost in the final to Serena Williams to take the silver medal.
As the defending champion and number two seed at the Italian Open, Sharapova had a bye in the first round. She battled through the second round against 20 year-old Christina McHale and prevailed 7–5, 7–5. She then faced thirteenth seed Ana Ivanovic and won 7–6(4), 6–3 in 1 hour 47 minutes to advance to the quarterfinals. Sharapova then defeated former world No. 1 Venus Williams 6–4, 6–3, meaning that Sharapova has reached the quarterfinals or better in all nine tournaments she has played this year. In the semifinals, Sharapova avenged her defeat to Angelique Kerber in Paris earlier in the year by beating her 6–3, 6–4 to advance to the final for the second year in a row. In the final, Sharapova saved match point for a 2 hour 52 minute, 4–6, 6–4, 7–6(5) win over Li Na for her 26th career title. This marked the fourth time Sharapova had successfully defended a title.
Sharapova was seeded 2nd at the French Open where she showed her dominance by defeating Alexandra Cadanțu in the first round in 48 minutes by the score of 6–0, 6–0. Sharapova then defeated Sara Errani in both competitors' first French Open final (and a first Grand Slam final for Errani). By reaching the final, she regained the world No. 1 ranking. Coincidentally, the last time Sharapova was No. 1 was right before the 2008 French Open, due to the sudden retirement of then No. 1 Justine Henin, a four times Roland Garros champion. [73] Sharapova became only the 10th woman to complete a career grand slam with the French Open 2012 victory.[74] She is the 6th woman in the open era to achieve the career grand slam, joining Steffi Graf, Martina Navratilova, Margaret Court, Chris Evert, and Serena Williams.[75] During the tournament, Sharapova was also asked by the Russian Olympic Committee to carry the Russian flag in this year's Olympic Games.[76]
Sharapova then extended her win streak to 15 matches when she competed in the Wimbledon Championships as the No. 1 seed there for the first time in her career. However, she was upset in the fourth round by 15th-seeded Sabine Lisicki, whom she beat in last year's semifinals. The score was 6–4, 6–3. As a result, she lost her No. 1 ranking, taken back by Victoria Azarenka.
She played in the 2012 Summer Olympic Games in London, her first Olympics. She was the flag bearer for Russia during the Olympics Parade of Nations. Seeded 3rd in the tournament, she won her first round match against Israeli player Shahar Pe'er.[77] She then defeated Great Britain's Laura Robson to reach the third round, where she avenged her 2012 Wimbledon loss to Sabine Lisicki by beating her 6–7(8), 6–4, 6–3.[78][79] In the quarterfinals, Sharapova defeated fellow former no. 1 Kim Clijsters by 6–2, 7–5 to advance to the semifinals, where she faced her compatriot, Maria Kirilenko. Sharapova defeated Kirilenko 6–2, 6–3 to reach the Olympic Final, where she lost to Serena Williams 0–6, 1–6,[80] marking her worst defeat to the American. With this performance, Maria overcame Agnieszka Radwanska as world no. 2.
Sharapova was seeded 3rd at the US Open, but had no hardcourt tune-ups after the Olympics due to a stomach virus. At the US Open, she made it to the semifinals before losing to top seeded Victoria Azarenka in three sets.
Sharapova's next tournament was the Toray Pan Pacific Open in Tokyo. She made it to he quarterfinals, losing to Sam Stosur 4–6, 6–7(10)only the 2nd lost to the Australian in 12 career meetings. At the China Open she was seeded second. She made it to the finals, en route defeating Angelique Kerber in the quarterfinals and Li Na in the semifinals. There she faced Azarenka in their fourth final and fifth match overall against one another this year. Sharapova lost to Azarenka 3–6, 1–6.
Her next tournament will be the year-end championships in Istanbul, where she will be seeded 2nd. She faced Sara Errani in her first round robin match, defeating her 6–3, 6–2. She secured a spot in the semifinals with a 5–7, 7–5, 7–5 win over Agnieszka Radwańska in her next match. Sharapova defeated Sam Stosur in her final round robin match, 6–0, 6–3. In their sixth meeting of the 2012 season, Sharapova defeated Victoria Azarenka, 6–4, 6–2. Although she has made it to the final, Azarenka clinched the year-end number one ranking with her two round robin wins. Thus, Sharapova will end the year as world no. 2. She lost to Serena Williams in the final, 6–4, 6–3.
Sharapova played an exhibition match in Prague, and won both her matches, defeating Petra Kvitova 6–1 and Lucie Safarova 7–6.
