Del Potro hailed the win and insisted it was out of hardwork and determination that he has extensively invested during his training..
“I think I played my best match of the tournament, I did everything well,” said the 24th seeded Argentine. “I served so good, I hit my forehand as hard as I could and I think we played a great match and I think I deserved to win.”
Federer had predicted that he would need to overcome Del Potro’s serve, forehand and fighting spirit to advance to the semi-finals.
Del Potro victory was welcomed by cheerful crowd where he expressed his gratitude to all fans who had gathered in large numbers.
“I think it’s my home court, too, you make me feel happy everytime I play here and I love your support guys. I love to see you cheer for me,” he told the crowd. “After all my injuries and surgeries … New York is my favourite tournament, my favourite city to play tennis.”
Federer, who is suffering from back problems, barely sat during the period between sets, and he broke for 3-1 with a forehand passing shot as Del Potro started to struggle with his first serve and the Swiss effortlessly claimed the set.
However, Federer dropped his serve in the second game of the third set when he served another double fault. He saved another break point in the fourth game, setting up one for himself in the seventh, which Del Potro gave away with a double fault.
Federer was on the brink of defeat when he trailed 0-30 on his serve at 5-3 and while he regained his strength to win the game the power had shifted and Del Potro hit another forehand winner in the next game.