Quality finishes either side of half-time from the French and Argentinian strikers proved the difference between the two teams, who meet again in Milan for Tuesday's second leg, with the winner of the Bayern Munich-Bayer Leverkusen German derby lying in wait.

A lively opening quarter in Rotterdam's ever-atmospheric De Kuip saw three-time European champions Inter enjoy most possession but Feyenoord carve out the clearest opportunities.

Ibrahim Osman, the pacy 20-year-old Ghana international winger on loan from Premier League side Brighton and Hove Albion, was the main threat for the hosts, twice forcing Josep Martinez into sharp saves.

For the visitors, Thuram found himself with a clear run at goal but decided to pass square rather than shoot and the danger was snuffed out.

It was a moment of quality from the French striker that broke the deadlock with just eight minutes until the half-time whistle, latching onto a curling cross from Nicolo Barella to hook it in with the outside of his boot at the far post.

The goal, slightly against the run of play, galvanised the Serie A side, who suddenly looked much more dangerous going forward.

Feyenoord legend and recently installed manager Robin van Persie would have been glad to get his side into the dressing room just 1-0 down after an entertaining first half.

But his side's arrears doubled just five minutes into the second period, as Martinez drilled an unstoppable shot into the top corner, giving the hosts a mountain to climb.

Jakub Moder came close to getting Feyenoord back into the game when his lunging deflection skimmed the bar.

Inter had their own chance to put the game -- and probably the tie -- beyond reach when Jeyland Mitchell brought down Thuram in the box, the referee awarding a penalty after a long VAR check.

But Timon Wellenreuther in the Feyenoord goal produced an excellent save from Piotr Zielinski's penalty, moving smartly to his right.

Feyenoord pressed to the end looking for something to take to the San Siro but the Inter defence held firm in a pleasing night for Simone Inzaghi's men.