The Champions League draw for the Round of 16 takes place this Thursday, Dec. 20, at 5:30 a.m. ET.

While there are a handful of teams being billed as contenders due to their top form this season, no team will be more feared than Barcelona.

No club that finished second in their group will want to face the current leaders of Spain right now. Last year's semifinalists are the most in-form team in football this season, along with Bayern Munich.

La Blaugrana are undefeated in La Liga and are on pace to break the total-points record set just last season by Real Madrid.

No Easy Draw

Despite being one of the top favorites to win the tournament, it would be simply foolish to think that Barcelona will not struggle in every match going forward.

If we have learned anything in the last two-and-a-half years of European play, it is that the Champions League is only getting more competitive and that there is no such thing as an easy match after the group stages.

Barcelona will be favored against whomever they draw in the next round, but there are some matchups that the players and coaches would probably prefer over others, even if they don't make that sentiment public.

The possibilities for the Spanish giants are Porto, Shakhtar Donetsk, Arsenal, Galatasaray and AC Milan.

Let's take a look at the best- and worst-case draws for Barcelona in the Champions League Round of 16.

Best-Case Draws

Galatasaray

There really is no easy draw for anyone at this point. The two teams listed here are in great form in their domestic leagues and will trouble any team.

No disrespect is intended toward either of these teams, but many Cules would be happiest to be drawn against Galatasaray or AC Milan.

Galatasaray won their last three Group H games but relied on head-to-head results to get out of what was probably the easiest group in the tournament.

The Turks are far east from Barcelona but not in a climate that will be as troublesome for visitors as Eastern European cities.

Milan

Milan areone of the hottest teams in Italy right now, being undefeated in their last five games, and played Barça very tough in their quarterfinal matches last season.

However, the Italians do not have a great record against Spanish clubs in recent seasons, and the current La Liga table-toppers are included in that run.

Milan have either been knocked out of the tournament or finished behind a Spanish club in their group in each of the last four seasons.

Worst-Case Draws

Shakhtar Donetsk

Of all the teams that finished second this year, only Real Madrid are feared more than the Ukrainian champions.

The Ukrainians are in top form domestically, losing just one match this season and winning their other 17 matches.

They also finished second in perhaps the second-toughest group and played a large role in sending the reigning champions, Chelsea, out early.

Shakhtar Donetsk play in a colder climate, too, which would make it harder for the Spaniards to get a result away. Their stout but aggressive defense would also make it tough for Barça at Camp Nou.

Arsenal

The lone English possibility is no longer one of Europe's elite teams and not a major contender, but they play a brand of football that Barcelona struggle against.

Many people see the results teams like Celtic and Chelsea got against Barça but fail to realize that the super-defensive strategy fails far more than it succeeds against them.

A team like Arsenal, on the other hand, is not afraid to go after Barcelona, exposing their defensive frailties and keeping lots of pressure on their midfielders.

The fast, quick passing game of the Gunners gives good opportunities for them to catch Barça out of position and keep them away from their own goal.

The team does not have the great scoring threat in Robin van Persie anymore, but they have better finishers than the likes of Celtic and Chelsea did, and only a few chances are needed to beat the Spaniards.

Feel free to let us know whom you think the best- and worst-case scenarios for Barcelona are below.

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