With the Champions League knockout round beginning today, let's determine each team's chances in the first leg. Using ESPN's Soccer Power Index (SPI) we calculated the offensive, defensive and overall rating of each team and used those to simulate each matchup 10,000 times. Here's a look at the four matches this week.

Bayer Leverkusen vs. Barcelona

Barcelona, the second-highest-rated club in Europe according to SPI, is the most heavily favored side in the four matches, winning in 64 percent of the simulations despite being the away side. Barcelona had no trouble away from home in the group stage, winning all three of its matches. Barca scored 12 goals in those three matches, five more than any other team in the competition. Leverkusen comes in on a bit of a cold streak, having won one of its six Bundesliga matches since the group stage ended.

Lyon vs. Apoel Nicosia

Apoel Nicosia is the first team from Cyprus to reach the knockout round of the Champions League, winning Group G despite scoring only six goals in its six matches, the fewest of any team to qualify for the knockout round. Lyon, which has never faced a team from Cyprus, allowed seven goals, keeping three clean sheets in the process. Lyon has allowed one or fewer goals in nine of its 11 matches since the group stage, and is 5-2-1 in all competitions in 2012.

AC Milan vs. Arsenal

AC Milan looks to avoid elimination by an English club in the round of 16 for the fourth straight time, including a 2-0 aggregate defeat to Arsenal in 2008. Milan conceded eight goals in the group stage, second-most among the remaining teams, but Arsenal scored just seven times, tied for the second-fewest of the final 16 teams.

These teams are similarly rated by SPI, but with the match being played at the San Siro, SPI gives Milan a significant advantage in the first leg. Milan has lost just one of 11 league matches at home this campaign, while Arsenal's win at Sunderland on Saturday was its first away from the Emirates in nearly two months in all competitions.

Zenit St. Petersburg vs. Benfica

NOTE: Neither league is tracked by the Soccer Power Index, so projections are calculated solely based on Champions League play over the past four seasons.

The first-ever meeting between the two sides comes with both clubs riding long unbeaten streaks. Benfica has not lost in the Portuguese Liga this season, winning 15 of 18 matches, and went 3-0-3 in the group stage. Zenit's most recent loss was 15 matches ago, a 2-1 loss to Apoel in the first match of the group stage, and the Russian side has never lost to a Portuguese opponent at home. The Russian league is currently on its winter break, and this is Zenit's first competitive match since late November, but SPI gives them the advantage as the home side.