Former Basle striker Breel Embolo marked his return to St Jakob Park with the opening goal and Admir Mehmedi curled home a fine second for the Swiss on the half-hour mark.

Portugal, still missing captain Cristiano Ronaldo to the injury he suffered in the Euro 2016 final win over France, could find no way back as they came out second best in the battle between the top two teams in Group B.

Switzerland, who missed out on a quarter-final date with Portugal at the Euros after losing a last-16 penalty shoot-out with Poland, took the lead in the 24th minute through Embolo's header.

The 19-year-old, a familiar goalscorer on this ground before swapping Basle for Schalke over the summer, pounced to nod home after Portugal goalkeeper Rui Patricio had pushed out Ricardo Rodriguez's free-kick.

It became 2-0 just six minutes later when Mehmedi linked up with Haris Seferovic following a rapid counter-attack before firing a pinpoint effort into the top corner from near the edge of the box.

Portugal boss Fernando Santos made a double substitution at the break, but it did little to change his side's fortunes and Switzerland midfielder Blerim Dzemaili should have killed the game off with 20 minutes to go only to fluff his lines.

Nani, wearing the captain's armband in the absence of Ronaldo, missed a similarly gilt-edged chance for Portugal with eight minutes left when he headed Ricardo Quaresma's cross against a post.

A goal then could have made things interesting, especially as Switzerland saw Arsenal playmaker Granit Xhaka sent off in stoppage time after picking up a second yellow card, but the home side held on relatively comfortably for the points.