NEW YORK (AFP) - Sobs turned to lobs as an emotional Dinara Safina stormed into the quarter-finals of the US Open, defeating German qualifier Anna-Lena Groenefeld 7-5, 6-0 on Monday. Safina's coach Zeljko Krajan had to raise Safina's spirits before she would agree to take the court against the 141st-ranked Groenefeld on the 10,000-seat Armstrong Stadium. "After the warm up I just started to cry. I could not stop crying," Safina said. "My coach said, 'Just go out there'. "I said, 'I cannot push anymore myself'. He said, 'We know that you're not a machine. Just go out there and don't think. "He told me again, 'just please don't show me any emotions, like these negative emotions. If you want, don't show even positive. Just go on the court and do whatever you can on this day. "Slowly I started to feel like I still can push myself. I am really happy that I won." It's already been an incredible year for Safina and a win at the US Open would be a fitting exclamation point for the 22-year-old Russian. But winning three titles and reaching the final of six of seven tournaments since the start of May is also wearing on her nerves and body. "He (Krajan) said if it's 20 percent left from your body, just give this 20 percent. Don't use another percent just throwing the balls around and shouting," Safina said. Safina is trying to follow in the footsteps of brother Marat and win her first Grand Slam at the US Open. Safina moves through to the quarter-finals where she will square off against Italy's Flavia Pennetta who dominated former world number one Amelie Mauresmo of France 6-3, 6-0. Safina was runner-up at the French Open earlier this year, giving credence to the argument she is the most in form of all the women's players on the WTA Tour. Marat won his initial Grand Slam at the US Open in 2000 and Safina, who won the silver medal at the Beijing Olympics, is hoping to do the same. "It will be the dream come true," she said. The special bond she has with her brother and Krajan has helped her reach her full potential. "I have grown up a lot in the mind," she said. "A year ago I would not be able to do these kind of things. "Even the match before against (Timea) Baczinsky (third round) I would have already lost. But somehow I started like to control better myself. "If you have a trust in your coach and you know he understands you and I understand him so that makes it easier for me to express my emotions. "Some coaches don't want to hear that you are tired. Or maybe they will not believe you that you are tired.  They will say, 'No, this is an excuse because you don't want to lose'. Of course, if I go on court then I want to win."