The second leg of the Champions League quarterfinals begins Tuesday, so let's take a look at each team's chances of advancing to the semifinals. Using ESPN's Soccer Power Index (SPI), we calculated the offensive and defensive ratings of each team and then matched them to determine their odds of advancing. Here's a look at the four matches this week.

Real Madrid -- Apoel Nicosia (Madrid leads 3-0)

Real Madrid takes a nearly insurmountable lead into the second leg, scoring three away goals in Cyprus last week. SPI gives APOEL a 2.0 percent chance of scoring the three or more goals it needs at a minimum in this leg to advance. Madrid has conceded three or more goals in a match only twice in all competitions this campaign, both of which came against Barcelona.

Madrid has won 26 of the 27 matchups in which it has won the first leg on the road, and APOEL has lost all ten times in which it has lost in the first leg at home. In addition, Madrid is riding a 16-match unbeaten streak in all competitions which dates back to its last home loss, a 2-1 defeat to Barcelona in the Copa del Rey in January. Factoring in all of that, giving APOEL a 0.1 percent chance might be generous

Chelsea -- Benfica (Chelsea leads 1-0)

Chelsea also comes in with an away win in the first leg. The Blues are a heavy favorite according to SPI because of their defensive rating, as Benfica is held scoreless in 41.5 percent of the match predictions. Chelsea has won all four home matches in this season's competition, scoring 14 goals and conceding only one. Benfica has not reached the semifinals since 1990, going goalless in its last two quarterfinal appearances. However, each of its last two semifinal appearances has resulted in the Portuguese side reaching the final.