UEFA Champions League 2013: Ranking This Week's Most Compelling Matchups

The Champions League is back!

Now is when club football's most prestigious competition becomes truly intriguing, at the knockout stage. While we'll have to wait until next week to see a few matchups between European giants such as Arsenal and Bayern Munich or AC Milan and Barcelona, Tuesday and Wednesday is chock full of action.

That includes the tastiest matchup of the tournament thus far. Let's rank each Champions League game scheduled for this week.

4. Celtic vs. Juventus

Celtic is always dangerous at home, and we all sat in stunned amazement when the Scottish side upset Barcelona in group play. But it's really, really hard to imagine Juventus losing or even drawing here, even on the road. 

Juventus currently sits atop the Serie A table by five points and has carried over the momentum from a 2011-12 campaign that saw the team win the Seria A title and reach the Coppa Italia final, only to lose to Napoli. 

Between Andrea Pirlo, Arturo Vidal and Claudio Marchisio, among others, there is simply too much magic on the Italian side for Celtic to fend off. Juventus will win the first leg, 1-0.

3. Shakhtar Donetsk vs. Borussia Dortmund

You might be inclined to underestimate the Ukrainian side Shakhtar Donetsk in this one, but think again. This is a team that survived a group with Juventus and Chelsea and plays the sort of exciting, free-flowing game that will at least make this game fun to watch.

Plus, Shaktar will have the home crowd behind them.

But this is a very talented Borussia Dortmund side led by Robert Lewandowski, Mats Hummels, Marco Reus and Mario Götze. Plus, Dortmund is likely already out of the running for the Bundesliga title, so everything hinges on a good showing in Europe.

Dortmund is one of the most dangerous teams in this tournament, and the German side will be well on its way to advancing to the next quarterfinals after defeating Shaktar in the first leg, 2-1.

2. Valencia vs. PSG

Paris Saint-Germain is one fire and hasn't lost since December 1. Then again, Valencia has lost just twice in its last 10 games, and both matches were against Real Madrid. Oh, and the team also tied Los Blancos and Barcelona in that spell.

PSG clearly has the more talented roster. But Valencia plays in the tougher league and is certainly battle-tested. Still, with the likes of Zlatan Ibrahimovic, Kevin Gameiro, Javier Pastore, Jérémy Menez, Thiago Silva and, oh yes, David Beckham, PSG should ultimately advance.

But Valencia will have the home crowd at its side, so I'm envisioning a 1-1 draw.

1. Real Madrid vs. Manchester United

Cristiano Ronaldo faces his old team. Sir Alex Ferguson and Jose Mourinho battle wits. The best team in arguably the best league in the world, Manchester United, takes on arguably the second most talented roster in the world (because it's hard to dispute Barcelona at No. 1 right now).

How much fun will this game be?

It would be easy to give Los Blancos the clear-cut advantage playing this one at Estadio Santiago Bernabéu, but keep in mind that United haven't lost in any competitions since a meaningless Champions League game against Cluj on December 5.

The Red Devils are on fire. This game should be brilliant, and I think it will finish in a 2-2 draw.