- Jonas heads in moments after Domenico Criscito's red card
- Zenit's first competitive game since 9 December
- Axel Witsel, Ezequiel Garay and Javi García all start against former side Benfica
- García, Criscito, André Almeida and Jardel ruled out of second leg
- Round of 16 second leg takes place at Stadion Petrovskiy on 9 March
Benfica will take a narrow lead to Russia in three weeks after Jonas headed in a last-gasp winner against flagging opponents.
Zenit looked set to hold on for a goalless draw when Domenico Criscito conceded a late foul, earning his second booking in the process. The defender was still making his way down the tunnel when, from the resulting free-kick, Jonas rose to head in the only goal of this UEFA Champions League last-16 first leg.
If this was the victory Benfica had sought after their weekend defeat by Porto, it still fell short of the backlash visiting coach André Villas-Boas had predicted. Indeed, it was Zenit who had made much of the early running, with their fluid attacking quartet keeping the Eagles grounded inside their own half.
André Almeida and Jardel picked up yellow cards that rule them out of the return fixture, but for all their purpose and energy the St Petersburg outfit were not really creating much. Jonas did at the other end, lashing a deflected effort just wide as Benfica asked a few questions of their own.
Axel Witsel, one of three former Benfica players in the Zenit starting XI, had a couple of attempts early in the second half yet gradually the Russian side ran out of gas in their first competitive outing for nine weeks.
The attacks of cramp did not go unnoticed and the hosts pressed on. Goalkeeper Yuri Lodygin got in the way of one thunderous effort from Nicolás Gaitán but there would be no stopping Jonas.
Key player: Jonas
Only Napoli's Gonzalo Higuaín has bettered Jonas's haul of 23 league goals this season in Europe's top divisions and the Brazilian's class shone through again as he took his chance after 90 minutes of frustration.