Former world number one Maria Sharapova eased past fellow Russian Ekaterina Makarova 7-5 6-1 today to reach the Stuttgart Grand Prix quarter-finals and continue her winning comeback from a 15-month doping ban. In the last eight stage, the Russian will clash against Estonian qualifier Anett Kontaveit.The 30-year-old Russian, who has won five Grand Slams and is among the highest-paid athletes in the world, returned to action yesterday with a straight sets win over Roberta Vinci following her suspension for the use of banned substance meldonium. Sharapova had tested positive at the 2016 Australian Open.