Switzerland's Breel Embolo scored the only goal against Cameroon - the country of his birth - in a hard-fought World Cup Group G opener.
Embolo refused to celebrate when he finished off a slick Swiss attack shortly after half-time.
The Indomitable Lions were unfortunate to lose after an enterprising display at the Al Janoub Stadium in Qatar.
Victory was vital for Switzerland, as both sides still have to face Brazil in the group.
- 'He is my little brother' - Cameroon boss praises Swiss match-winnerHow the game unfoldedFifa World Cup: Groups & ScheduleWorld Cup TV Coverage guide
Embolo moved to Switzerland from Cameroon with his family as a six-year-old and pledged his allegiance to the European nation after being granted citizenship in 2014.
At the age of 18, he set up the Embolo Foundation to support refugee children in Switzerland and disadvantaged children in the country of his birth.
He said before the game it would be "a very special" occasion to play against Cameroon and when he scored, he respectfully raised his arms and closed his eyes.
"I told him, 'Breel, friendship until the start, then they are your opponents,'" said Switzerland coach Murat Yakin. "Football writes such stories but he completed his mission.
"I am very happy with his performance."
Cameroon boss Rigobert Song admitted afterwards he would "have liked him to be on my side" but did say he was "proud" of Embolo.
"We are all proud of our country and you saw he did not celebrate the goal," said Song. "That is part and parcel of football and I'm proud of him."
Embolo's strike ensured victory for a side with high expectations - Yakin has declared his squad "the best Switzerland side ever" and said he expects them to achieve their best return at a World Cup.
After the game, captain Granit Xhaka echoed his coach's comments, arguing "we can beat anyone" and pointing to their record in recent tournaments as evidence of their potential.
Yet Switzerland struggled in the first half in the face of a vibrant Cameroon start and ought to have gone behind, with Eric Choupo-Moting, Bryan Mbeumo and Martin Hongla all missing presentable opportunities.
The goal rocked Cameroon and the Swiss had chances to extend their lead, only for Andre Onana to save superbly from Ruben Vargas, while Embolo and substitute Haris Seferovic were denied by last-ditch defending.
The Indomitable Lions have now lost eight successive games at the World Cup finals but Song's side impressed at times here.
Song admitted afterwards their next game against Serbia will be "decisive" if they are to stand any chance of becoming the first Cameroon team to progress beyond the group stage since 1990.
For Switzerland, the win gives them breathing space before their match against group favourites Brazil on Monday.
Player of the match
with an average of 7.70
SwitzerlandAvgSquad number10Player nameXhakaAverage rating
Squad number23Player nameShaqiriAverage rating
Squad number8Player nameFreulerAverage rating
Squad number7Player nameEmboloAverage rating
Squad number5Player nameAkanjiAverage rating
Squad number13Player nameRodríguezAverage rating
Squad number9Player nameSeferovicAverage rating
Squad number1Player nameSommerAverage rating
Squad number3Player nameWidmerAverage rating
Squad number4Player nameElvediAverage rating
Squad number17Player nameVargasAverage rating
Squad number15Player nameSowAverage rating
Squad number20Player nameFreiAverage rating
Squad number25Player nameRiederAverage rating
Squad number19Player nameOkaforAverage rating
Squad number18Player nameCömertAverage rating
CameroonAvgSquad number13Player nameChoupo-MotingAverage rating
Squad number20Player nameMbeumoAverage rating
Squad number23Player nameOnanaAverage rating
Squad number5Player nameOndouaAverage rating
Squad number12Player nameToko-EkambiAverage rating
Squad number10Player nameAboubakarAverage rating
Squad number6Player nameNgamaleuAverage rating
Squad number3Player nameNkoulouAverage rating
Squad number14Player nameOum GouetAverage rating
Squad number25Player nameToloAverage rating
Squad number18Player nameHonglaAverage rating
Squad number8Player nameAnguissaAverage rating
Squad number21Player nameCastellettoAverage rating
Squad number19Player nameCollins FaiAverage rating
Squad number7Player nameNkoudouAverage rating
- Line-upsMatch StatsLive Text
- 1Sommer3Widmer5AkanjiBooked at 83mins4ElvediBooked at 64mins13RodríguezSubstituted forCömertat 90'minutes8Freuler10Xhaka23ShaqiriSubstituted forOkaforat 72'minutes15SowSubstituted forFreiat 71'minutes17VargasSubstituted forRiederat 81'minutes7EmboloSubstituted forSeferovicat 72'minutes
23Onana19Fai Collins21Castelletto3Nkoulou25Tolo8Anguissa14Oum Gouet18Hongla20Mbeumo13Choupo-Moting12Toko-Ekambi
- 23Onana19Fai CollinsBooked at 36mins21Castelletto3Nkoulou25Tolo8Anguissa14Oum Gouet18HonglaSubstituted forOndouaat 68'minutes20MbeumoSubstituted forNgamaleuat 81'minutes13Choupo-MotingSubstituted forAboubakarat 74'minutes12Toko-EkambiSubstituted forNkoudouat 74'minutes
- 1Ngapandouetnbu2Ngom Mbekeli4Wooh5Ondoua6Ngamaleu7Nkoudou9Nsame10Aboubakar11Bassogog15Kunde16Epassy17Mbaizo22Ntcham24Ebosse26Marou
Referee:Facundo TelloAttendance:39,089Match StatsHome TeamSwitzerlandAway TeamCameroonPossessionHome51%Away49%ShotsHome7Away8Shots on TargetHome3Away5CornersHome11Away5FoulsHome12Away10Live TextPost update
Match ends, Switzerland 1, Cameroon 0.
Second Half ends, Switzerland 1, Cameroon 0.
Manuel Akanji (Switzerland) wins a free kick on the right wing.
Foul by Georges-Kévin Nkoudou (Cameroon).
Corner, Switzerland. Conceded by Jean-Charles Castelletto.
Attempt blocked. Haris Seferovic (Switzerland) left footed shot from the centre of the box is blocked. Assisted by Fabian Rieder with a headed pass.
Corner, Switzerland. Conceded by Nouhou Tolo.
Substitution, Switzerland. Eray Cömert replaces Ricardo Rodríguez.
Foul by Gaël Ondoua (Cameroon).
Fabian Rieder (Switzerland) wins a free kick in the defensive half.
Attempt saved. Granit Xhaka (Switzerland) left footed shot from outside the box is saved in the bottom right corner. Assisted by Noah Okafor.
Foul by Moumi Ngamaleu (Cameroon).
Ricardo Rodríguez (Switzerland) wins a free kick in the defensive half.
Manuel Akanji (Switzerland) is shown the yellow card for a bad foul.
Foul by Manuel Akanji (Switzerland).
Frank Anguissa (Cameroon) wins a free kick in the defensive half.
Corner, Switzerland. Conceded by Nicolas Nkoulou.
Substitution, Cameroon. Moumi Ngamaleu replaces Bryan Mbeumo.
Substitution, Switzerland. Fabian Rieder replaces Rubén Vargas.
Foul by Fabian Frei (Switzerland).
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