With the spectre of Brazil looming later in the group for both teams, three points at the Al Janoub Stadium on Thursday was a must and it was the Swiss who deservedly grabbed the win, despite a few early scares.
Cameroon enjoyed by far the more clear-cut chances in an open but goalless first half, with Eric Choupo-Moting and Bryan Mbeumo both seeing their finessed efforts parried away by Swiss keeper Yann Sommer.
Switzerland – who pushed both France and Spain to penalties at Euro 2020 – endured a quiet start, but fashioned two big-headed chances later in the half.
Nico Elvedi's stooping but misdirected header from a 40th-minute corner went wide, while Manchester City star Manuel Akanji ought to have tested Andre Onana from close range when latching onto Vargas' whipped corner, but could only glance it wide.
It didn't take the European side long to break the deadlock after the half-time interval, as Embolo finished a slick move when he turned home Xherdan Shaqiri's cross from the right with a cool side-footed finish.
From there, the Swiss looked to assert their authority and put the game to bed. They had big chances to double the lead through Embolo again, and Granit Xhaka, but safely saw out the narrow, and crucial, victory.