Images from Wednesday's Champions League matches
Real Madrid, Schalke 04, FC Porto all in action
Madrid's players react during a free kick during the last sixteen, first-leg UEFA Champions League football match FC Schalke 04 vs Real Madrid in Gelsenkirchen, western Germany on February 18, 2015.PATRIK STOLLARZ/AFP / Getty Images
Schalke's midfielder Marco Hoeger, right, and Real Madrid's Brazilian midfielder Lucas Silva vie for the ball during the last sixteen, first-leg UEFA Champions League football match FC Schalke 04 vs Real Madrid.PATRIK STOLLARZ/AFP / Getty Images
Schalke defenders Atsuto Uchida, left and Benedikt Hoewedes vie for the ball with Real Madrid's French forward Karim Benzema.ODD ANDERSEN/AFP / Getty Images
Real Madrid's Welsh forward Gareth Bale and Schalke's defender Dennis Aogo vie for the ball.ODD ANDERSEN/AFP / Getty Images
Real Madrid's Cristiano Ronaldo, centre, scores the opening goal past Schalke's goalkeeper Timon Wellenreuther, left,and Schalke's Joel Matip, right looks on during the Champions League round of 16 first leg soccer match between FC Schalke 04 and Real Madrid.Frank Augstein/The Associated Press
Porto's Hector Herrera, right, challenges FC Basel's Shkelzen Gashi during their Champions League round of 16 first leg soccer match in Basel, February 18, 2015.ARND WIEGMANN/Reuters
Schalke's defender Dennis Aogo, left, shoots a free kick during the last 16, first-leg UEFA Champions League soccer match FC Schalke 04 vs Real Madrid.ODD ANDERSEN/AFP / Getty Images
Real Madrid's Gareth Bale, left, and Schalke's Matija Nastasic go for a header during the Champions League round of 16 first leg soccer match between FC Schalke 04 and Real Madrid.Frank Augstein/The Associated Press
Real Madrid's Toni Kroos, right, is booked by referee Martin Atkinson during the Champions League round of 16 first leg soccer match between FC Schalke 04 and Real Madrid.Frank Augstein/The Associated Press
Schalke's Atsuto Uchida, front, and Real Madrid's Cristiano Ronaldo challenge for the ball during the Champions League round of 16 first leg soccer match between FC Schalke 04 and Real Madrid.Frank Augstein/The Associated Press
Schalke 04's Dennis Aogo collides with Real Madrid's Gareth Bale during their Champions League Round of 16 first leg soccer match.INA FASSBENDER/Reuters
Basel's Swiss midfielder Luca Zuffi and Porto's Brazilian defender Alex Sandro go for a header during the UEFA Champions League round of 16 first leg soccer match between Basel (FCB) and Porto (FCP) on February 18, 2015 at the St. Jakob-Park stadium in Basel.MICHAEL BUHOLZER/AFP / Getty Images
Porto's Colombian forward Jackson Martinez, left, vies with Basel's Swiss midfielder Taulant Xhaka during the UEFA Champions League round of 16 first leg match between Basel and Porto.MICHAEL BUHOLZER/AFP / Getty Images
Basel players celebrate their first goal against Porto during their Champions League round of sixteen first leg soccer match at the St. Jakob-Park stadium in Basel, Switzerland, Wednesday, Feb. 18, 2015.Patrick Straub/The Associated Press
Porto's Brazilian midfielder Casemiro, right, celebrates with a teammate after scoring an equalizer that was later not allowed by the referee for offside positions, during the UEFA Champions League round of 16 first leg football match between Basel (FCB) and Porto (FCP) on February 18, 2015 at the St. Jakob-Park stadium in Basel.FABRICE COFFRINI/AFP / Getty Images
Supporters of Schalke 04 party in the stands during their Champions League Round of 16 first leg soccer match against Real Madrid in Gelsenkirchen, February 18, 2015.WOLFGANG RATTAY/Reuters
Basel's Czech defender Marek Suchy, bottom, fouls Porto's Colombian forward Jackson Martinez during the UEFA Champions League round of 16 first leg match.FABRICE COFFRINI/AFP / Getty Images