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Seferovic opened his account with a 10th-minute header following a cross from former Fulham winger Pajtim Kasami.
Kasmi hit the crossbar two minutes prior to Seferovic's second - a powerful left-footed shot into the bottom corner.
Galatasaray midfielder Dzemaili increased the away side's advantage further on the half-hour mark when he rose to nod home the delivery of full-back Ricardo Rodriguez, who had got to the left byline.
Chances continued to come Switzerland's way, but a home defence which has conceded 25 goals without reply was not breached again until the 78th minute when Bayern Munich winger Shaqiri thrashed into the roof of the net from close range.
Rodriguez's stoppage-time penalty miss prevented the Swiss from matching England's 5-0 win over the minnows.
The world's number 10 ranked team have three points from three games, having previously lost to England and Slovenia.