It was one of Maria Sharapova's great serving performances of the year and one of Venus Williams' most ineffectual excuses of the year.
"The first problem for me was just I was so tired today. I don't know why. I'm usually not tired. I was just so tired," Williams repeated herself after Sharapova, never broken in this one hour and 17-minute semifinal, blasted to a 6-4, 6-3 victory that put her into the Nasdaq-100's championship match Saturday against Kim Clijsters.
Clijsters easily reached the final by crushing top-seeded Amelie Mauresmo, 6-1, 6-0, to become the first unseeded woman to reach the title match in the 21-year history of the tournament.
Sharapova, the tall, 17-year-old Russian phenomenon, won 36 of her first 45 service points and never let Williams get to deuce until the final, frantic game, when Venus mounted her only rally.
She had six chances to break and get back on serve at 4-5, beginning with a love-40 lead, but was repulsed by Sharapova's nervy, aggressive tennis.
And when it was over, ending her best run on Key Biscayne since 2002, Williams had every opportunity to grace her conqueror with praise.
Instead, her most glowing concession was, "I think she played fairly consistent, definitely. Definitely."
Sharapova stifled a laugh when apprised of Williams' "fatigue," then chose diplomacy over outrage.
"I'll just say I thought I played really well. I was in control for most of the match and I was serving really well, and getting a lot of advantage from them."
If Williams had dead legs, there was no sign of it on court. She ran hard and competed at a high level. It would be closer to the truth to say she was ultimately crushed by two factors: Sharapova's serving and her own wayward forehand.
It's a shot that has routinely disappeared from Williams' repertoire in big matches over the years, though two nights earlier, in a monumental triumph over her sister, Serena, her forehand never seemed more lethal against a top-10 player.
One match later, it was once again on the fritz.
And so Sharapova extends her record for the year to 22-2 and reaches her third final, having won titles at both Tokyo and Doha and is now in position to win her 10th WTA tournament.
This match could have been headed for a third set if Williams had seized her opportunities with Sharapova serving at 5-3.
But from love-40, Williams struck a forehand service return into the net, then a wild forehand long to the forehand corner and then Sharapova got to deuce with a sharp backhand down the line that left Williams a stretch forehand that she netted.
There would be three more break point opportunities. Williams fired a shot into the net at the end of a forehand-to-forehand rally for one, Sharapova slammed a brilliant serve down the T from the ad court and Williams hit a backhand long.
When Williams' 24th and final unforced error landed well behind the baseline, Sharapova headed for the handshake, pumping her fist.
In beating Mauresmo for the seventh time in a row, Clijsters showed all the staying power she exhibited in her ground stroking against Elena Dementieva in the quarters, and her serving was impeccable.
In the opening set, she won 10 of 12 second-service points and Mauresmo failed to convert four break point opportunities. The French woman's spirit was broken early in the second set as Clijsters blazed through her in 27 minutes, outscoring her, 27-10.
Clijsters already had a game plan for Saturday's final: "I have to be very aggressive right from the start because when she gets into that rhythm she's very difficult to beat."