Into the second half and Moyes made six changes, withdrawing the likes of Captain Cresswell, Fabiański, Dawson, Manuel Lanzini and Michail Antonio and introducing Kurt Zouma, Issa Diop and 17-year-old Mubama.
The latter took no time to make his mark, forcing Frick into a smart save before scoring with a neat backheel from close-range on 52 minutes after the goalkeeper had parried Saïd Benrahma’s low shot.
The home side again sought a response and hit the frame of the West Ham goal, this time when No8 Timothé Cognat’s chip clipped the crossbar. The same player then rolled a shot a yard wide after being played clean through, much to his evident frustration with him as he then kicked the air and the pole supporting the goal net.
With Servette manager Alain Geiger making multiple changes to his team and Moyes introducing two more substitutes himself, the game then lost its shape and flow, as so often happens in warm-up fixtures.
Nevertheless, the West Ham supporters among the 4,188-strong crowd on a warm evening in Geneva made sure the atmosphere did not follow suit, singing enthusiastically in support of their respective teams.
One of Geiger’s replacements, Dimitri Oberlin, saw a shot blocked by Zouma and another dribble narrowly past substitute Nathan Trott’s post, and West Ham held out to keep a clean sheet and start their seven-match pre-season campaign with a win.
West Ham United: Fabiański (Trott 46), Ashby, Dawson (Diop 46), Alese, Cresswell © (Zouma 46), Coventry, Lanzini (Ekwah 46), Fornals (Chesters 60), Benrahma (Okoflex 60), Masuaku (Longelo 46), Antonio (Muhamma 46)
Subs not used: Randolph (GK), Hegyi (GK), Ogbonna, Potts
goals: Alese 27, Mubama 52
Servette: Frick©, Diallo, Pflucke, Cognat, Antunes, Severin, Rodelin, Behrami, Doulin, Bedia, Vouilloz
Subs used: Omeragic (GK), Rouiller, Cespedes, Stevanovic, Oberlin, Valls, Magnin, Bauer, Monteiro, Ndema, Dias Patricio