Milan/St. Petersburg, Feb 16 (IANS) Arsenal's dream of winning the Champions League football came to a grinding halt as they were thrashed 0-4 by AC Milan in the first leg of their last-16 clash at San Siro. Russian side Zenit St. Petersburg scraped past Benfica 3-2 at Petrovski Stadium.

From the outset Arsenal looked out of sorts as the home team piled on the pressure in a match played in Milan Wednesday. Kevin-Prince Boateng opened the scoring for Milan in the 15th minute with a wonderful volley. Brazilian forward Robinho scored a brace in the 38th and 49th minute before Zlatan Ibramohvich capped off a perfect game for the Italians with a penalty in the 79th minute.

Arsenal never gained a foothold in the game as they slumped to their heaviest European away defeat. Wenger surprisingly gave a start to Welsh midfileder Aaron Ramsey, who has looked far from convincing all season. Alex-Oxdale Chamberlain and Frenchman Thierry Henry, who was in the final game of his loan spell from New York Red Bulls, came off the bench but could not spark a fairytale comeback for the English team.

Arsenal will have to put in an inspired performance to overcome a four goal deficit in the second leg at home March 6.

Zenit had to fight hard to win at home as they came back from a goal down to win a thriller against the Portuguese side in a game held in St. Petersburg. In freezing conditions, Uruguayan Maxi Pereira gave Benfica the lead after an error by Zenit goalkeeper Yuri Zhevnov.

Zenit in their first appearance at the knockout stage of the Champions League, drew level in the 27th minute thanks to Roman Shirokov's well placed volley. After the break Sergei Semak completed a brilliant move by his teammates to give Zenit the lead in the 71st minute.

Benfica looked to have snatched a draw as Oscar Cardozo scored in the 87th minute. However, their joy was short-lived as Shirokov scored his second in the 89th minute to give Zenit all three points.