Serena Williams edges sister Venus at US Open to maintain calendar Grand Slam quest

World number one Serena Williams beat sister Venus to reach the US Open semi-finals ©Getty Images

World number one Serena Williams maintained her quest for her first calendar Grand Slam as she booked her spot in the semi-finals of the US Open with a three-set victory over sister Venus at Flushing Meadows in New York City.

Six-times champion Serena, bidding for her fourth consecutive triumph, battled through thanks to a 6-2, 1-6, 6-3 win over the 23rd seed, competing in a US Open quarter-final for the first time since 2010.

Men’s top seed Novak Djokovic is also through to the last four after he overcame Spain’s Feliciano Lopez in four sets.

In front of a packed-out 23,000 crowd at Arthur Ashe Stadium, the top women's seed breezed to the opening set and looked as though she would go on to record a comfortable success but Venus fought back valiantly to threaten to end her sister’s Grand Slam dream.

Venus managed to level proceedings thanks to a much-improved performance in the second-set as she sent the tense match, the sisters’ 27th meeting on the professional circuit, into a decider.

The seven-times Grand Slam winner was unable to deal with Serena’s power from the baseline, however, as the defending champion showed why she remains the one to beat, taking the third set and with it a place in the last four.

It keeps her chances alive of becoming the first player to win all four majors in a calendar year since Germany’s Stefi Graf achieved the remarkable feat in 1998.

“She's the toughest player I've ever played in my life and the best person,” Serena said.

“It's going against your best friend and the greatest competitor, for me, in women's tennis, so it was really difficult for me today.”

Serena will now go up against Italian Roberta Vinci, who reached unchartered territory, sealing a place in a Grand Slam semi-final for the first time, beating Frenchwoman Kristina Mladenovic 6-3, 5-7, 6-4.

Croatian Marin Cilic won a five-set epic with Jo-Wilfried Tsonga to reach the last four of the men's competition ©Getty Images

In the men’s draw, defending champion Marin Cilic of Croatia survived a fightback from France’s Jo-Wilfried Tsonga to secure his berth in the last four, claiming victory in a five-set thriller.

The contest between the two hard-hitters lasted two minutes shy of four hours, which seemed unlikely when Cilic, ranked number nine in the world, raced into a two-set lead.

Tsonga launched a spirited comeback, however, to level the pulsating contest, before Cilic, whose triumph at Flushing Meadows last year gave him his first Grand Slam crown, emerged with a 6-4, 6-4, 3-6, 6-7, 6-4 victory.

Cilic has a tough task on his hands if he is to secure the US Open title for the second year in a row as he will come up against world number one and nine-times Grand Slam champion Novak Djokovic in the semi-final after the Serbian top seed beat Feliciano Lopez of Spain.

Djokovic wasted little time in taking the first set but Lopez, fourth at the London 2012 Olympic Games, hit back to square the match.

It was to be a mere fleeting moment of success for the Spaniard as Djokovic ensured he remained on course for a second US Open crown, winning 6-1, 3-6, 6-3, 7-6.