St Petersburg - Roman Shirokov scored his second goal of the game in the 89th minute as Zenit St Petersburg beat Benfica 3-2 in the first leg of their round-of-16 matchup in the Champions League on Wednesday.

Maxi Pereira put Benfica ahead in the 20th, tapping the ball in after second-choice goalkeeper Yuri Zhevnov spilled Oscar Cardozo's free kick, but Shirokov equalized seven minutes later.

Substitute Sergei Semak made it 2-1 with a backheel in the 71st.

Cardozo levelled for the visitors in the 87th after Zhevnov again failed to hold a shot, and the game appeared headed for a 2-2 draw until a defensive blunder by Pereira gifted Shirokov his second goal - and his fifth in seven Champions League games - from short range.

Zenit, making its debut in the knockout phase, was missing seven key players through injury and illness in its first game of the year. The Russian champions haven't lost at home in European competition since 2008.

The Portuguese club was previously unbeaten in the tournament and came through after finishing top of Group C, which included Manchester United.

After a scrappy start in freezing conditions at Petrovsky Stadium, the game kicked into life after Pereira's opener.

Aleksandr Kerzhakov came close with a volley at the back post and Shirokov fired over the bar in a flurry of action before the equaliser.

The Portuguese team struggled to keep Zenit out and started to threaten again only after playmaker Pablo Aimar replaced the injured Rodrigo on the half-hour mark.

Benfica, unbeaten this season in the Portuguese league, was the more stylish team in the second half as Aimar and Nicolas Gaitan tormented the home team's defence with slick ball skills.