Alexander Zverev apologised in the face of heckles from the O2 Arena crowd for a controversial incident in his 7-5 7-6 (7-5) ATP Finals victory over Roger Federer.
Zverev became the first German since Boris Becker in 1996 to reach the final but drew the ire of sections of the auditorium when he stopped playing mid-point during the second-set tie-break.
A ballboy behind Federer dropped a ball which rolled towards the court, the eventually replayed point going the way of Zverev, who went on to see out the match.
Zverev, 21, was booed as he started his on-court interview by some who deemed him to have gained an unfair advantage and he immediately moved to apologise for the incident.
"First of all I want to apologise for the situation in the tie-break," he said. "The ballboy dropped the ball and it's in the rules that we have to replay the point."
Interviewer Annabel Croft also reminded the crowd of the rules and urged spectators to be "a little bit more respectful" to Zverev, who played superbly and will face Novak Djokovic or Kevin Anderson in the final.
Zverev continued: "I apologised to Roger at the net already and he said it's okay, that's obviously in the rules like that.
"I want to apologise to the crowd as well. I know there are a lot of Roger fans here. As he deserves, he should [have a lot of fans].
"For what he's achieved and the kind of guy he is, he should have the most fans in the world. And obviously here in London, especially, with how much history he has here.
"The crowd has been amazing and fair the whole match. I'm very sorry that this happened. I didn't mean to upset anybody. That's all I can say. Sorry."
Tournament director Adam Hogg later tweeted: "Astonishingly disappointing reaction from the crowd.
"Huge credit to Sascha Zverev for reaching his first final here at the ATP Finals. And well done Annabel Croft on handling the situation with aplomb."
Astonishingly disappointing reaction from the crowd.— Adam Hogg (@acphogg) November 17, 2018
Huge credit to Sascha Zverev for reaching his first final here at the #NittoATPFinals.
And well done @Annabel_Croft on handling the situation with aplomb.
|Muller could miss Champions League last 16 after Tagliafico kick|
|Home hope Bekker out in front at Alfred Dunhill Championship|
|Van Bommel in touch with Robben over PSV reunion|
|Pinarello chief confident over Team Sky future|
|Stade make Ospreys tickets free in tribute to teenager|
|WRC great Loeb seals Hyundai switch|
|Madrid rumours better than sack talk, says Pochettino|
|Nadal to join Federer at 2019 Laver Cup|
|Prigoda smashes world record, Hosszu dethroned in Hangzhou|
|Former Juve CEO Marotta takes over at Inter|
|Glenn to stand down as FA boss next year|
|Muller apologises to Tagliafico for kick to the head|
|Pereira pleads for more Manchester United chances|
|Griffin hails ´phenomenal´ Lowry after Warriors demolition|
|I´ve played with Zidane and Henry, but Messi is something else – Pires|
|Dragons forward Jack de Belin charged with sexual assault|
|Durant: Raptors are the real deal|
|Cocu bids farewell to Fenerbahce after ´mutual agreement´ is made over October sacking|
|Australia unchanged for historic Perth Test|
|Champions League draw: The possible last-16 ties|
|Southee happy to be back on home soil|
|I wouldn´t swap Dembele for Neymar – Pires|
|Canelo ready to risk heavy weather against Fielding|
|Raptors upstage Warriors, Davis leads Pelicans with 44 points|
|India skipper Kohli excited by green Perth wicket|
|PSG? I haven´t decided my future yet – De Jong|
|Marcelo: Real Madrid don´t have attitude problem|
|India pair Ashwin, Rohit ruled out of second Test|
|Kovac: Ajax-Bayern draw was amazing|
|Sims re-signs with Dragons until 2022|
|Derrius Guice injury update: Redskins RB (knee) has rehab setback, undergoes 3 more procedures|
|Emery: Arsenal could sign defender in January|
|Phillies sign McCutchen to three-year deal|
|O´Neal thinks his Lakers teams could ´easily´ beat Warriors|
|A-League to add two clubs by 2020|
|Curry says he was ´obviously joking´ about moon landing comments|
|Now the beautiful part starts – Ronaldo ready for Champions League knockout stage|
|Bayern have a lot more potential – Lewandowski not satisfied despite top spot|
|Lyon star Fekir shares plaudits for Champions League progression|
|Mourinho not surprised by United´s defeat to Valencia|
|Motivation no issue for Benfica, claims Vitoria|
|Lewandowski finishes Champions League group stage as top scorer|
|Mourinho: We scored two goals and lost 2-1!|
|England have a diamond - Guardiola hails City´s Foden|
|Sterling´s carefree display invites us to love football more than others hate|
|Juventus achieved their objective, despite everything going wrong – Allegri|
|Never say never - Schmidt not ruling out All Blacks role|
|Bologna´s winning start ended in BCL|
|Di Francesco critical of Roma performance|
|Shakhtar Donetsk 1 Lyon 1: Fekir fires French side through in Group F|
|Benfica 1 AEK Athens 0: Grimaldo sends hosts out on a high|
|Young Boys 2 Juventus 1: Hoarau double seals famous victory|
|Manchester City 2 Hoffenheim 1: City through as group winners after Sane brace|
|Ajax 3 Bayern Munich 3: Kovac´s men clinch top spot in Amsterdam thriller|
|Valencia 2 Manchester United 1: Jones scores own goal as Red Devils limp through|
|Solari accepts responsibility for Madrid´s heaviest home defeat in Europe|
|WATCH: Rooney backs Rocky ahead of Canelo showdown|
|McLaren to collaborate with Team Bahrain Merida|
|Las Vegas to host 2020 NFL Draft|
|Stade teenager tragically dies after neck injury|
|Cahill may need to leave Chelsea if he wants to play, admits Sarri|
|Viktoria Plzen 2 Roma 1: Chory winner takes hosts into Europa League|
|Real Madrid 0 CSKA Moscow 3: Champions humiliated at Bernabeu|
|Sarri condemns ´disgusting´ Sterling abuse|
|Hansen hails outstanding Ben Smith ahead of Pau switch|
|Foden, Sterling start for Manchester City v Hoffenheim|
|Sky decision will not affect us in 2019, insist Froome and Thomas|
|Al Ain 3 Team Wellington 3 (aet, 4-3 on penalties): Shootout heartbreak for semi-pros in Club World|
|Jackson to remain Ravens´ starting QB despite Flacco return|
|Rams headline 2019 NFL International Series home teams|