The Champions League round of 16 gets underway on Tuesday. Back in December we ranked the remaining 16 clubs based on their previous performances. On the eve of the actual round of 16, we will take another look at that list and see how the teams rank based on recent form. This is a discussion of which teams have the best chance to win the trophy, including a look at their upcoming matchups and how that affects each team's respective tournament chances.

16. Zenit St. Petersburg (Previous Rank 16)

The Russian giants remain at the bottom of the list for a number of reasons. The team has not played since December, a blessing and a great difficulty at the same time. Who knows how this team will look when it takes on Borussia next week and who knows whether the rest will actually pay off. Dortmund could be tired heading into the matchup, but the team has continued trekking along and will not suffer from any rust prior to this matchup.

15. AC Milan (Previous Rank 13)

The Italian side is unlikely to play in this tournament next season and if Atletico Madrid continues it tremendous play, this team will not get past this round. AC Milan has struggled in the domestic league and there is little reason to believe that it will make any difference in this tournament.

14. Olympiakos (Previous Rank 15)

The Greek side has been terrific in the domestic league and has not lost a single game against Greek competition this season. The team has never been seen as a major contender and will likely not go far in this tournament. However, a quarterfinals berth has become an increasing possibility mainly because of the team's upcoming opposition. Manchester United has struggled to find its form and is looking more and more like a team that can be defeated with relative ease.

13. Manchester United (Previous Rank 10)

If not for the names on this roster, United would probably see a bigger drop. David Moyes has been a disaster in his first year at the helm and could potentially see his time at the Old Trafford come to an end at the close of the season. He can salvage some dignity with a big turnout in this competition but do not expect a deep run past the quarterfinals.

12. Schalke 04 (Previous Rank 14)

Julian Draxler and company have played well of late with no losses in their last six Bundesliga matches and a big win over second-place Bayer Leverkusen. This team faces a big challenge in Real Madrid but if history rings true, a win at home could be a major possibility for the German side.

11. Bayer Leverkusen (Previous Rank 11)

The German side has been solid in the domestic league and there is little reason to believe that they are not capable of a big run. Paris Saint-Germain is the favorite in this tie and will likely prevail due to its dynamic scoring duo.

10. Galatasaray (Previous Rank 12)

The Turkish giants have gone 14 games in the Turkish league without a loss; the last defeat this team experienced took place back in October. The team is just six points out of first place and has looked increasingly dominant in recent weeks. Chelsea will be a tough opponent but do not overlook the talent and intensity that this team will bring to the round of 16.

9. Arsenal (Previous Rank 8)

How the mighty have fallen. Arsenal was once at the top of the Premier League and looked like a team of destiny. Its recent run of duds (a 5-1 loss at Liverpool and a 0-0 draw at home against Manchester United) has seemingly taken the wind out of Arsenal's sails and has made them look more beatable. The team recovered some dignity in a 2-1 win over Liverpool in the FA Cup but this is no longer a side that should intimidate Bayern Munich.

8. Manchester City (Previous Rank 6)

Another former top contender that has slowed down in recent weeks. A 2-0 win over Chelsea in the FA Cup is certainly something to savor but the offense is in a slump, exposing the mediocre defending and goalkeeping. Barcelona will likely run rampant in this round.

7. Atletico Madrid (Previous Rank 7)

Diego Simeone's team has slipped a bit in recent weeks but continues to look like a powerhouse club. Diego Costa is still the most feared striker in Europe and the return of David Villa should only strengthen this side. The fact that AC Milan continues to falter should only boost Atletico's chances of a deep run.

6. Paris Saint-Germain (Previous Rank 5)

The French champs have done little to convince anyone that they are incapable of a deep run. However, the teams above them in the rankings have continued to excel and are proving themselves worthier candidates. Bayer Leverkusen presents a tough challenge, but Zlatan Ibrahimovic and Edinson Cavani should not be fazed.

5. Borussia Dortmund (Previous Rank 4)

Last year's runner-ups struggled to establish themselves early on in the season, but Jurgen Klopp continues to prove that he is one of the best in the business at what he does. He has this team rolling with a four-game undefeated streak in the Bundesliga and is just one point from claiming second place in the league. Zenit will provide no difficulty for this team's championship aspirations, but who knows what the quarterfinals bring.

4. Barcelona (Previous Rank 3)

Los Cules are still a top side and the return of Messi has seemingly reinvigorated their offense. The problem with Barcelona, however, is that the team has been exposed defensively and has not quite made a case for taking on strong challenges. Manchester City will be a huge litmus test. If Barcelona wins, then expect its current ranking to soar; a loss in the first leg would be detrimental to the historic side's chances at a deep run.

3. Chelsea (Previous Rank 9)

Jose Mourinho may run his mouth a bit, but he sure backs his banter on the pitch. Or at least his team does. After some early season blues, Chelsea is cruising at the top of the Premier League and looking potent both offensively and, more importantly, defensively. The team lost against Manchester City in the FA Cup this weekend, but that is a minor blemish in what has been a terrific past few months.

2. Real Madrid (Previous Rank 2)

Los Blancos continue to soar and have not lost since an October match with Barcelona. Since then the team has exploded offensively and defensively. Cristiano Ronaldo has nine goals in the UCL this season while Gareth Bale, Jese and Angel Di Maria continue to prove their worth in the midfield and forward positions. Iker Casillas has not allowed a goal in months and will get the start against Schalke. This Madrid team looks invincible right now. However...

1. Bayern Munich (Previous Rank 1)

No one is going to top Bayern Munich. At least not with the way that the team is playing under Pep Guardiola. The team has lost one game in 2013-14; that match came against Manchester City in the final game of the Champions League group stage. Aside from that Munich has barely lost a point and continues to dominate teams offensively. Arsenal could provide a challenge but it is hard to imagine Guardiola making any tactical errors against a team that is losing its edge. Munich is still the favorite to win this tournament.