The stadium was larger, the weather sunny, dry, and windy rather than dark and humid, the crowd louder and partisan, the opponent desperate and determined rather than sluggish and slow. None of it mattered to Andy Murray, who will play in his first major final today against Roger Federer after a fabulous performance yesterday against world no. 1 Rafael Nadal, 6-2, 7-6(5), 4-6, 6-4.

These two faces of tennis’s future returned to Arthur Ashe Stadium late yesterday afternoon to complete a rain-delayed match. Murray, 21, had won the first two sets, but Nadal, 22, led by a break of serve in the second. Both men looked fresh at the start. Misses were rare and so were break points: Murray earned one, in the final game of the set, but Nadal cast it aside with a 120-mph ace and took the match to a fourth set.

The match seemed to swing in Nadal’s favor when he won a 15-minute game to tie the score at one in the fourth set, saving seven break points along the way. Nadal broke Murray at love and then held serve for a 3-1 lead. The next game, Murray lost the first two points on his serve. A fifth set seemed certain.

It’s moments like these when we learn the most about a tennis player. Earlier in this tournament, Murray kicked and screamed against Michael Llodra, a talented but inconsistent opponent. A round later, he found himself down two sets to none against Jurgen Melzer, ranked no. 48 in the world. Two rounds after that, he played timidly against Juan Martin Del Potro, the towering Argentine who hits the ball as hard as anyone in the game.

Yesterday, though, Murray showed unshakeable confidence. He escaped the 0-30 deficit, broke Nadal’s serve, and then put himself in the lead. The second-to-last point of the match was the best of the afternoon as both men pushed each other side to side and mixed in high-looping strokes with powerful drives. It was a combination of modern tennis — power from the baseline and severe angles — with the slices and deft touch of two decades past. Murray, a throwback player who was taught the importance of tactics by his mother Judy, once the national coach of Scotland, won out. A point later, a tired Nadal hit a drop shot that bounced too high and Murray ended the match by flicking a backhand into the open court.

Nadal said he was thankful for Saturday’s rain delay, as he lacked energy when this match began. The season, he said, has tired him. Nadal has played 84 matches already this year, won the French Open, won Wimbledon, captured the no. 1 ranking, and won the gold medal at the Beijing Olympics. Before yesterday, Nadal had won all five of his matches against Murray, including a rout at Wimbledon and a victory on a hard court this summer in Toronto that put him within reach of the no. 1 ranking. He said Murray might have played better in the first set on that day in Toronto, but he left no doubts about the depth of Murray’s talent.

“When he’s playing aggressive, he can beat everybody,” Nadal said.

When Murray was a junior, most scouts praised his hands. Put simply, Murray makes it look easy to control the ball — he is, in his own words, “a natural tennis player.” He changes the direction of his shots at the last moment, he has delicate touch at the net, and his reflexes are superb, as he showed when he flicked his racket at a bullet backhand from Nadal and hit a cross-court passing shot that gave him a 4-3 lead in the fourth set. Murray’s two-handed backhand relies largely on his left hand, which allows him to drive the ball down the line or angle it cross-court at the last second.

Murray’s timing is so exquisite that it often overshadows his other athletic gifts. He now stands 6-foot-3 and has broad shoulders. He’s fast, too, and adept at finding the shortest path between him and the ball. When Murray is in motion, he wastes few steps and little energy.

Like a young Federer, Murray’s shortcoming has been his mind. His temper can get the better of him. Oftentimes, he doesn’t know which of his many talents to use and when. It’s a battle he continues to fight — sometimes, as his earlier matches in this tournament indicated, with great difficulty. Federer, perhaps seeing a bit of his former self, criticized Murray the last time they met, in Dubai in February. Federer had just returned from a mononucleosis-induced layoff when Murray scored a two-sets-to-one victory, pushing his winning streak against Federer to two. Federer wasn’t impressed.

“He is going to have to grind it very hard in the next few years if he is going to play this way,” Federer said. “I gave him the mistakes but overall, in a 15-year career, you want to look to win a point more often, rather than wait for the other guy to miss. Who knows, he might surprise us all.”

If Murray plays today the way he did against Nadal the last two days, he just might.

Mr. Perrotta is a senior editor at Tennis magazine. He can be reached at tperrotta@tennismagazine.com.