A thrilling encounter saw Zverev hold on to beat Federer 6-3 6-7(7) 6-3 at the quarter-final stage in China.
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Fifth seed Zverev held off a stirring comeback from the 38-year-old, who produced some sublime tennis to fend off five match points and send the match to a decider.
And it was in that final set when Federer had a point deducted for unsportsmanlike conduct when he hit the ball into the air after losing a point, with a tense stand-off with the umpire following.
After the match, Federer dismissed a question about the penalty after saying his last point deduction was a “long, long time ago”.
“So you can write on Twitter you mean?” he said in response to a reporter’s question. “It would be nice to write something nice once also about the game… Next question.”
Zverev, who received plenty of coaching and words of encouragement from Federer when the pair teamed up at the Laver Cup, added: “Emotions in sport are great, I didn’t know what was happening with the umpire, I didn’t pay close attention.
“Every time he had an argument he started playing better as well, so maybe it was a way to help him as well.

Alexander Zverev and Roger Federer, Masters 1000 Shanghai

Image credit: Getty Images

“He will always find a way and that’s why he’s the best player of all time, because in difficult situations where his mind is not at its best he’ll still find a way to make it difficult for you.”
Federer was not the only big scalp to fall on Friday as Stefanos Tsitsipas claimed an impressive win against Novak Djokovic.
It means none of the ‘Big Four’ (Federer, Djokovic, Rafael Nadal, Andy Murray) are in the Shanghai semis for the first time since 2009.
And Federer says that is “exciting” for the sport despite his disappointing defeat.
“They’re knocking on the door big time the young guys, it’s exciting – they’re great. It’s really open now for the finish of this tournament.
It’s also quite exciting as the speed of the court is fast and guys have to come into the net a bit more as well.
“It was surprising to see Novak lose too even though Tsitsipas has been playing great so far. Maybe I was favourite also going into this match, but Sascha came out and had no serving issues today.
“He was able to produce a great game like he did against me in London. It’s an exciting time in tennis but nothing new there.”
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'I don't think his hands are that good' - Zverev coaches Ruud mid-match
Laver Cup
'I don't think his hands are that good' - Zverev coaches Ruud mid-match