BARCELONA, Spain (AP) — Hailed as perhaps soccer's greatest team ever, Barcelona faced a challenge no club had overcome: advancing in the Champions League after a 2-0 first-leg loss on the road.
Messi started the revival with a pair of first-half goals, and Barcelona overwhelmed AC Milan 4-0 Tuesday to reach its sixth straight Champions League quarterfinal with a 4-2 aggregate win.
Messi scored in the fifth and 40th minutes, and David Villa and Jordi Alba added second-half goals.
Messi then scored his second goal to Abbiati's left with a low 19-yard shot after Andres Iniesta stole the ball from Massimo Ambrosini.
"For anyone who doubted Messi, today Messi gave a lesson on how to play football," said Barcelona assistant coach Jordi Roura, in charge while coach Tito Vilanova undergoes treatment in New York for a saliva gland tumor. "He is extraordinary, and surrounded by great players, he is capable of doing what he does."
Villa put Barcelona ahead in the series in the 55th minute with a 14-yard shot after Cristian Zapata's weak clearance was intercepted by Javier Mascherano, and Kevin Constant missed a sliding tackle on Xavi's through pass to the forward.
Alba sealed the win in the second minute of stoppage time when he raced the length of the field on a counterattack after Messi stole the ball and passed to Alexis Sanchez on the break.
"Milan only needed a goal, but we knew how to handle the game very well," Alba said. "This is a very important win for us. A lot was at stake."
AC Milan, a seven-time champion, won the first leg at San Siro on Feb. 20 and nearly got a valuable away goal in the 38th minute, but 18-year-old forward M'baye Niang hit a post with an open shot after a sloppy headed backpass by Mascherano. If Niang had tied the game 1-1, Barcelona would have needed at least three more goals at that point to advance because away goals are a tiebreaker.
"Barcelona is still the best team in the world. Moving on was a true feat," Milan coach Massimiliano Allegri said. "The first leg didn't change these two teams, and whoever thought so was wrong. We played worse than in the first leg, but that is to Barcelona's credit."
Messi, the four-time FIFA Player of the Year, got his 18th multigoal game of the season and increased his season goals total to 53.
Led by the 25-year-old Messi, Barcelona is seeking its fourth Champions League title in eight years and is closing in on its sixth Spanish league championship in nine seasons. Barcelona is 16-0-4 at home in the Champions League since a loss to Ruben Kazan in October 2009.