Federer, 36, raced to a 6-1 6-3 victory in just 61 minutes against Frances Tiafoe in his hometown of Basel.
But midway through the second set his charge was delayed by a shout of ‘I love you’ from an over-enthusiastic local in the crowd.
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The call had fans in in hysterics and led to the briefest of delays in the match – although Federer’s concentration didn’t waiver as he powered to an easy win.
Federer has been married to wife Mirka since April 2009 but he last week admitted he’d never been to her homeland of Slovakia.
Mirka was born in 1978 in Bojnice but moved to Switzerland at the age of two.
And Federer has acknowledged he should have perhaps visited Slovakia at least once throughout their time together.
“Unfortunately, I often do not travel here,” he told Czech magazine VIP Sport.
“I played here a few years ago the Davis Cup, in February I was here to promote the Laver Cup and now I was with you and together with the team of Europe won it.”
But Federer described his failure to visit her hometown as ‘awful.’
“I know. That’s awful This is terrible!” he said.
“I know. Let’s not talk about it anymore, it’s really terrible.”