Nobody defeats Rafael Nadal easily. Yet on Saturday night in the second semifinal of the Shanghai Masters, Juan Martin del Potro came about as close as humanly possible to doing just that. Del Potro dismantled the No. 1-ranked Spaniard 6-2, 6-4 in a scintillating exhibition of power tennis. Yes, it took one hour and 46 minutes — certainly not a breeze — but Del Potro was in control virtually all the way. It was deja vu 2009 U.S. Open, when the 6-foot-7 Argentine handled Roger Federer in a similar display of powerhouse tennis. With the win, his first over Nadal in four years, Del Potro, ranked No. 5, secured a berth in the season-ending ATP World Tour Finals in London next month and also tomorrow’s final against Novak Djokovic. Del Potro came out of the blocks smoking, breaking Nadal in his first two service games and racing to a 4-0 lead. The Argentine kept the pressure on Nadal with depth, pace and precision, while utilizing the fast court conditions to his advantage. In the second game, Del Potro blasted a 152-mph forehand winner past a stunned Nadal that left the Spaniard smirking and shaking his head. “I played so solid all the time, hitting the ball so hard,” Del Potro said. “I saw Rafa playing very far off the baseline, which is good for my game, for my serve, and confidence. That’s the way to beat this guy.” Del Potro closed out the opening set in 45 minutes with an ace on his first set point. Threatening to make a statement, Nadal held at love to open the second set, and had two break points in the ensuing game but couldn’t cash either of them. The Argentine broke in the third game and stayed strong the rest of the way for the victory, his fourth in 12 career meetings with Nadal. “He played amazing. I just congratulate him,” Nadal said. “Very few times I play against a player with a level like today…I really go home with the feeling that I didn’t play bad. That’s the thing. It is fair to say that. I am humble enough to say that I played well and I lost 6-2, 6-4.” Del Potro hit 28 winners, including five aces, and won 66 percent of his service points. The Argentine takes a 3-9 record against Djokovic into Sunday’s final.