BEIJING — As Rafael Nadal stood in front of the medal podium, his nation’s flag draped across his back like a cape, he looked a little like a Spanish Superman.

In tennis, he is.

Already assured of the No. 1 ranking, Nadal was No. 1 at the Olympics. He won a gold medal today, overcoming two set points in the second set and holding every service game to beat Fernando Gonzalez of Chile 6-3, 7-6 (2), 6-3.

The gold medal was the first ever for Spain in Olympic tennis, and another milestone in an astounding summer surge by Nadal, who will officially end Roger Federer’s 4-1/2-year reign atop the rankings tomorrow. Nadal has won 38 of his past 39 matches, including victories over Federer in the finals at the French Open and Wimbledon.

“Nowhere in my best dreams I can imagine something like what I did this year,” Nadal said. “I know how difficult it is to win these things, and especially here, because you only have one chance every four years.”

Elena Dementieva earned the gold in women’s singles, taking advantage of 17 double-faults by fellow Russian Dinara Safina to win 3-6, 7-5, 6-3.

In women’s doubles, Venus and Serena Williams of America won the gold, beating Anabel Medina Garrigues and Virginia Ruano Pascual of Spain 6-2, 6-0. The sisters celebrated with shrieks, then shared a hug.

The Williams sisters failed to medal in singles but found considerable consolation in doubles, improving their lifetime Olympic record as a team to 10-0. They won the doubles gold at Sydney but didn’t play in Athens four years ago because Serena was hurt.

“It does mean more for me to win it with Serena, to share this kind of moment with your sister,” Venus said. “I mean, we are practically joined at the hip.”

Yan Zi and Zheng Jie of China beat Ukraine’s Alona and Kateryna Bondarenko for the bronze, 6-2, 6-2.

Russia swept the medals in women’s singles when Vera Zvonareva beat Li Na of China 6-0, 7-5 to win the bronze. That victory made Russia the first nation to win all three medals in one tennis event since Great Britain did so in the 1908 women’s singles.

Tennis was not a medal sport between 1924 and 1988.

Men’s singles has traditionally been an upset-filled event at the Olympics, and Nadal is the first player ranked in the top five to win the gold. He stayed in the athletes’ village and said the experience rejuvenated him.

“I arrived very tired,” he said. “The reason probably I won this title is because I have a fantastic time here enjoying a lot in the village. That was amazing experience for me. Always was a pleasure to know new people, no?”

He took charge against Gonzalez from the start, breaking serve in the second game. Nadal didn’t face any break points until the 12th game of the second set, when he was down 5-6, 15-40.

Gonzalez failed to convert the set points, pushing a volley wide and putting a forehand in the net. The Chilean made five unforced errors in the tiebreaker to give Nadal a commanding lead.

Nadal ripped a backhand passing shot to break at love for a 3-1 lead in the final set, and erased two more break points to hold for 5-2.

He needed four match points to close out the victory, ripping one last Olympian forehand that Gonzalez could barely reach. Nadal collapsed to his back in jubilation.

“I think I played almost perfect match,” he said.

Gonzalez settled for a silver medal after winning a gold in doubles and a bronze in singles four years ago in Athens.

“I have chances in the second set, and I didn’t take it,” Gonzalez said. “After that, Rafa was dominating. He was make me run a lot. He’s a great champion, because he has been winning every important tournament in the past months.”

Another test is around the corner, and now expectations will be high. Even though Federer has won four consecutive U.S. Open titles, Nadal will be seeded No. 1 when the tournament begins Aug. 25.

The No. 5-seeded Dementieva closed out her victory with a forehand winner, then fell to her knees before walking to net for a congratulatory hug from Safina. Dementieva, who won the silver medal at Sydney in 2000, snapped Safina’s 15-match winning streak.

“I never expected a medal — gold, silver or bronze,” Dementieva, 26, said. “It’s unbelievable. For me this is the best moment in my career. I’ll never forget it.”

Dementieva has been plagued for much of her career by a shaky serve, but it was a frustrated Safina who struggled to put the ball in play. After double-faults she flung her racket, banged it against the concrete and smacked a ball into the stands, but the tantrums failed to help.

Dementieva also packed more punch from the baseline and hit twice as many winners, 26 to 13.

She lost her first three service games and needed 14 points to hold for a 1-0 lead in the second set, giving her a toehold in the match. A flurry of errors by Safina in the final game of the second set helped Dementieva break to even the match.

Safina said she felt the toll of playing nine matches — three in doubles — in the past week.

“I was not the freshest today physically,” she said. “To serve, you have to push yourself up, to jump up. And when the legs are a little bit slow, it just doesn’t go.”