Andrea Ranocchia's last-gasp header has sealed a dramatic 3-2 victory for Inter Milan in their Coppa Italia quarter-final with Bologna.

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The visitors began well, taking the game to Andrea Stramaccioni's men in the opening half hour.

They nearly took the lead through Cristian Pasquato, but Samir Handanovic was on hand to palm away his driven shot.

Federico Agliardi was then called upon to stop Antonio Cassano's curling strike, but the Nerazzurri took the lead soon after through Fredy Guarin.

The Colombian international unleashed an unstoppable drive from the edge of the area that Agliardi was powerless to stop.

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Rodrigo Palacio looked to have sealed Inter's progression amid controversial circumstances in the 79th minute.

Bologna were furious as they believed the ball had gone out of play in the buildup to the goal, but Inter played on and the Argentine put his team on the precipice of the semi-final.

However, two goals in as many minutes stunned the San Siro faithful.

Alessandro Diamanti clipped a delightful free kick just under Handanovic's bar in the 82nd minute, before Manolo Gabbiadini headed home Marco Motta's cross to force extra time.

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Javier Zanetti had the first meaningful chance in the extra 30 minutes, as both teams dropped the pace.

The Argentine saw his initial effort repelled by Agliardi and could only slot wide of the post from the rebound.

Bologna's two goalscorers then linked up with four minutes remaining, but Gabbiadini could not generate any power on his header from Diamanti's cross.

Penalties loomed large with 120 minutes on the clock, but there was still time for one last throw of the dice from Inter.

Palacio did well to win a corner, which Guarin sent into the box for Ranocchia to head past Agliardi.

The Nerazzurri will now face the winner of the last quarter-final between Roma and Fiorentina.