Switzerland reached the World Cup knockout phase for the third straight time after prevailing 3-2 over Serbia on Friday to finish runners-up in Group G and set up a last 16 showdown with Portugal.

In a contest that ebbed and flowed at breakneck speed in the first half at Stadium 974, Xherdan Shaqiri put Switzerland ahead but Serbia swiftly scored twice within 10 minutes through Aleksandar Mitrovic and Dusan Vlahovic to flip the game on its head.

Breel Embolo delivered another twist in an absorbing opening period by pulling Switzerland level just before the break, while Remo Freuler scored three minutes after the restart to restore their one-goal advantage again.

"It was a tough game and we battled back bravely," said Gregor Kobel, who deputised for Yann Sommer after the first-choice goalkeeper was ruled out due to illness.

"It was my first international match for some time and to have such an elimination game was something I enjoyed as a challenge. It was certainly not the easiest game. At the end, we are very happy to have won this."

Switzerland had fired warning shots with barely 30 seconds on the clock, as captain Granit Xhaka's strike was blocked by the Serbian defence before goalkeeper Vanja Milinkovic-Savic denied both Embolo one-on-one and also Xhaka on the rebound.