The move started with Albrighton hitting a long cross field pass out to the right for Mahrez, who curled a left-foot cross to the far post where Slimani headed powerfully past Casillas. Slimani always scores against Porto.

It was the Algeria international’s seventh goal in seven games against Porto, his previous six coming for Sporting Lisbon against the Dragons prior to his €32m record summer signing by Leicester.

On the hour mark Porto coach Nuno Espirito Santo, changed his 4-3-3 system to try to get a toe hold in midfield.

Portugal international Danilo dropped deeper as the visitors subsequently controlled more of the game. Porto were looking good for an equaliser and Leicester were lucky to survive a nervous final fifteen minutes.

The substitute Hector Herrera had a shot pushed away by Schmeichel and Jesus Corona struck the Leicester post with a cracking shot with seven minutes remaining as Ranieri’s team retreated in the face of waves of attacks.

When Porto won the Champions League under Jose Mourinho in 2004, Leicester were relegated from the Premier League – the start of a ten year spell away.

They have come a long way back and they look set to stay in this competition beyond Christmas having collected maximum points from their two games.

FC Porto with just one point from two games, now face a uphill struggle to make the knockout stages.

Sporting Lisbon defeated Legia Warsaw 2-0.

After the heartbreaking loss at Real Madrid in their group opener, when leading until the 89th minute, Sporting rebounded with another good performance and secured the three points at home against the group's weakest team.

Sporting are just one point behind Real Madrid and Borussia Dortmund, which drew 2-2 in Germany. Sporting came close to opening the scoring when midfielder Gelson Martins hit the crossbar.

Costa Rican playmaker Bryan Ruiz put the home side ahead in the twenty-eighth minute after Legia midfielder Miroslav Radovic failed to fully clear a cross.

Dutch striker Bas Dost continued his impressive form by doubling the lead from close range, eight minutes before the interval. It was his fifth goal in as many games after arriving from German club Wolfsburg in the summer