It's been billed as the game of the year by no less an eminence than Sir Alex Ferguson. He's not blowing smoke.

Real Madrid travel to England's sodden, chilly North-West to take on Ferguson's Manchester United in a critical, winner-take-all Champions League knockout game on Tuesday ( LIVE on FOX Soccer from 2 PM ET with Gus Johnson and Warren Barton). Drawn 1-1 after the first leg at the Bernabeu three weeks ago, United arguably have the advantage with an away goal in their back pocket. But Los Merengues enter on a massive high, having trashed arch-rivals Barcelona not once but twice in back-to-back Clasicos.

The truth is simple: this is potentially the most exciting, most attack-minded game on the football calendar this season. United will throw Robin van Persie, Wayne Rooney, Danny Welbeck and Shinji Kagawa against a Madrid side that boasts Angel Di Maria, Kaka, Karim Benzema, Gonzalo Higuain - and United's former star, Cristiano Ronaldo.

It doesn't get much better than this.

Both sides are desperate to win and progress to the quarters of Europe's grandest club tournament. But there is an extra edge in Jose Mourinho's Spanish charges. Despite their takedowns of Barcelona, Real threw away too many points at the beginning of their season and the league title is almost certainly out of reach. Even if Barcelona were to complete what would be an historic swan dive into the pavement, their crosstown rivals, Atletico Madrid, remain above Real in the table. Realistically, Real is looking at the domestic Cup and the big-eared jug that is the reward for European triumph.

United, on the other hand, have the potential to complete a treble: they sit 12 points ahead of rivals Manchester City atop the English Premier League table and seem destined to collect their 20th title; await a battered Chelsea in the FA Cup quarterfinals, and cannot be dismissed as a European threat.

Yet, dismissed is exactly what United were when this matchup was announced. The thinking was that this United was less-than-vintage, a team overly reliant on van Persie, and given to plodding displays in a league that most would agree has slipped from its heights. Real, despite their domestic woes, would surely sweep the English aside, much as Barcelona did in a memorable display at Wembley two years ago.

United, perhaps relishing its underdog status, has instead confounded observers and began running teams over. They shocked Real with a youthful display of attacking exuberance, and look to repeat the feat.

United enter the game on as a high a note as can be: they haven't lost a game since December 5th of last year, a remarkable 18-game streak across all competitions. And where United started as England's version of the heart-attack kids - conceding early goals only to claw back to victory 17 times this season - they have settled into a lustrous groove since the New Year: ten wins, two draws, no losses.

More problematic for Real is that United is nearly impossible to beat at Old Trafford. They've only lost two home games this season: one, a defeat to Tottenham that snapped a 23-year-long home winning streak against their Premiership rivals; the other, a loss to Cluj in the Champions League after United had already qualified and Ferguson decided to play a weakened team.

United has been helped by a fairly weak schedule - they have played just a single team in the top half of the table since mid-January - but the Red Devils have developed a swagger and a sense of invincibility. The early season woes - shoddy defending, doubts over the fitness of Rio Ferdinand and Nemanja Vidic, some questionable goalkeeping - seems to have if not addressed, then papered over well enough. In fact, the most-criticized member of Ferguson's squad, young keeper David de Gea, had a show-stopping performance in his hometown against Real, and his confidence seems to be at an all-time high.

But beating up the likes of Norwich and Reading isn't quite the same as knocking Barcelona to the ground twice in a row. Real was similarly embattled earlier this season, with talk of a dressing room revolt, bitter recriminations after losses and the presumed departure of a weary-looking Mourinho grimly hanging over the team.

What beating your hated rivals can do: Ronaldo seems to have discovered another gear in what was already a world-class footballing engine, looking dangerous no matter where on the pitch he collects the ball. The emergence of Raphael Varane as a legitimate starting central defender has more than covered up the loss of Iker Casillas (injured) in the net and Real Madrid now look like a team playing with a purpose other than ousting their notoriously controlling manager.

Both teams have soft spots: United's defense, in particular Jonny Evans, can be exploited. Real's Pepe is always one rash moment away from a sending-off. And both teams look far more comfortable streaming forward than they do tracking back.

But that means goals, and that's what fans everywhere want to see - so who cares? Expect both teams to go hell for leather towards each other's nets, and expect a shootout at Old Trafford. This one's got classic already stamped all over it.

NOTES: Ferguson told the press yesterday that he was "shocked" at how Real used their counterattack to deadly effect against Barcelona. "They played some textbook counter-attacking football," said Ferguson. "That's their strength." ... Ryan Giggs is set to receive his 1000th senior cap in the game. Said Ferguson of the honor: "He deserves it."