Scalding heat, hail storms, and sudden showers that impacted the first week in Melbourne were merely a prelude for the perfect storm that rolls into Rod Laver Arena tonight.

World No. 1 Rafael Nadal and sixth-seeded Roger Federer square off for the 33rd time with a spot in the Australian Open final at stake. The pair have combined to win 30 of the last 42 major titles and meet in their first Grand Slam clash since Nadal defeated Federer in the Aussie Open semis two years ago, 6-7 (5), 6-2, 7-6 (5), 6-4. Each man has surrendered just one set so far as they renew a rivalry that dates back to the 2004 Miami Masters. Nadal won the first meeting and has relied on his heavy topspin, counter-strike skills, and competitive ferocity to reel off eight of their last 10 matches, seizing a 22-10 stronghold on an iconic rivalry he approaches in primal terms.

“The only thing that I know is that I have to play my best, and I [am] going to try,” said Nadal, who withstood both Grigor Dimitrov and an expanding blister on the palm of his racquet hand that left the top seed feeling like he was losing his grip on serve.

A banged-up Nadal’s average first-serve speed against the 22nd-seeded Bulgarian was about 11 M.P.H. slower than the 115 M.P.H. first-serve speed he averaged in a 12-ace, one double-fault performance against Kei Nishikori in the fourth round. Playing with tape wrapped around his palm, Nadal showed signs of fragility in a horrific three double-fault game to donate a break to Dimitrov, and concedes that the blister causes complications.

“I feel that with the tape I can lose the racquet when I’m serving,” said Nadal, who practiced on Thursday without taping around his palm. “That's a terrible feeling for a serve, because then when you have this feeling you are not able to accelerate at the right moment.”

As for Federer, imposing his faster tempo of play will be a priority in a match where tactics, confidence, and conditions will all play significant roles. Here’s the encouraging news for Federer fans: Despite Nadal’s 8-2 advantage in their major meetings, conditions are suited for the Swiss’ all-court attacking style. Players say the court is playing a bit faster and eliciting a slightly lower bounce, which should favor Federer, who has been tormented by Nadal’s hellacious shoulder-high lefty topspin to his one-handed backhand in the past. The weather forecast calls for an 80 percent chance of rain, which means the retractable roof over Rod Laver Arena will likely be closed. That could create a faster track and cleaner conditions for the flatter-hitting Federer.

Armed with a new racquet and coach—childhood idol Stefan Edberg—the 32-year-old is serving with authority (winning 83 percent of his first-serve points and 61 percent of his second-serve points), moving beautifully, and has launched the Fed-berg era with forward thinking that saw him win 49 of 66 trips to net in his quarterfinal victory over Andy Murray. Look for Federer to slide the wide serve to Nadal’s backhand on the deuce side and tee off on any short replies with his forehand. If Roger is to halt his four-match slide to Rafa and earn his first major win over his nemesis since the 2007 Wimbledon final, he must serve superbly, consolidate break point chances, and apply the all-court attack he's shown in reaching his record-extending 11th consecutive Australian Open semifinal.

“The racquet's not going to do the running for you,” Federer said, adding. “I definitely think that's what I used to do so well, you know, the transition game from defense to offense. I definitely sensed that today I am back physically. I'm explosive out there. I can get to balls…I’m looking forward to the next match.”

While Federer finds himself playing catch-up against Nadal, the 13-time Grand Slam champion can take another step toward closing the gap in the major title race and continue his quest to become the first man in the Open era to win each of the four majors twice. The Spaniard’s court coverage, confounding topspin combinations, and mid-match adjustments—Nadal typically alters his return position more frequently than Federer—are all assets. Rafa has invoked a fail-safe pattern—his crosscourt forehand to Roger’s backhand—to dominate this rivalry in recent years. Can Federer play the bold tennis required to flip the script?

Federer is the most complete player I’ve seen; Nadal is the most resilient. Based on current form, I favor Roger. Based on sheer defiance, I favor Rafa.

The last time I discounted Nadal Down Under was mistakenly believing he’d be too drained from winning a five-hour, 14-minute semifinal duel with Fernando Verdasco to fend off Federer in the 2009 final, and we know how that turned out. Federer is playing more dynamic tennis right now, but Nadal has a remarkable ability to raise his level of play to meet the required challenge.

The Pick: Nadal in five sets