Dominic Thiem has compared facing John Isner’s serve to a football goalkeeper in a penalty shootout after beating the American on Friday for a place in the Mutua Madrid Open semi-finals.
Speaking after his 3-6, 6-3, 6-4 win on Friday, Thiem admitted, “I think it's comparable to a goalkeeper [facing] a penalty. If he places it well, if it has the right speed, there's just no time to react.
“You either have to guess or hope that he's missing the first serve. It's just pure luck actually to return it. It's like a 50/50 chance. That's why it's so, so tough.”
Isner, who has struck 12,582 aces over the course of his career according to Infosys ATP Stats, hit 107 aces in his fourth matches this week at the ATP Masters 1000 tournament in Madrid.
“It's not only the first serve, it's the second as well, which has such a high bounce,” said Thiem. “You go close, return it, which is unbelievably tough, especially here on clay in altitude, or you go five, six metres back behind the baseline. He has a lot of time to come in the net. It's just incredibly tough to be a returner against him.”
100+ ACES IN A CLAY-COURT TOURNAMENT (since 1991)
It was the third time that Isner had hit 100+ aces in a clay-court tournament.
Third seed Thiem, who has also beaten Marcos Giron and Alex de Minaur this week, is competing at his first tournament since losing to Lloyd Harris on 16 March at the Dubai Duty Free Tennis Championships.
“I'm pleased with everything [in] my game,” said Thiem. “I’ve played three very different opponents. Everything is working quite well. [My] groundstrokes are working well. The serve was pretty good all the time. The return today, especially in some parts of the game, was very good.
“I guess that I'm on the right [path] definitely. But still many things to improve, getting 100 per cent back in the match rhythm, anticipation and everything… I am surprised to be in the semi-finals.”
Thiem will play fifth seed and 2018 titlist Alexander Zverev of Germany on Saturday.
Speaking after his 3-6, 6-3, 6-4 win on Friday, Thiem admitted, “I think it's comparable to a goalkeeper [facing] a penalty. If he places it well, if it has the right speed, there's just no time to react.
“You either have to guess or hope that he's missing the first serve. It's just pure luck actually to return it. It's like a 50/50 chance. That's why it's so, so tough.”
Isner, who has struck 12,582 aces over the course of his career according to Infosys ATP Stats, hit 107 aces in his fourth matches this week at the ATP Masters 1000 tournament in Madrid.
“It's not only the first serve, it's the second as well, which has such a high bounce,” said Thiem. “You go close, return it, which is unbelievably tough, especially here on clay in altitude, or you go five, six metres back behind the baseline. He has a lot of time to come in the net. It's just incredibly tough to be a returner against him.”
100+ ACES IN A CLAY-COURT TOURNAMENT (since 1991)
It was the third time that Isner had hit 100+ aces in a clay-court tournament.
| Player | Aces | Tournament (Result) |
| Martin Verkerk (NED) | 124 | 2003 Roland Garros (F) |
| John Isner (USA) | 110 | 2014 Roland Garros (4R) |
| Michael Stich (GER) | 108 | 1996 Roland Garros (F) |
| John Isner (USA) | 107 | 2021 Mutua Madrid Open (QF) |
| John Isner (USA) | 101 | 2017 Internazionali BNL d'Italia (SF) |
Third seed Thiem, who has also beaten Marcos Giron and Alex de Minaur this week, is competing at his first tournament since losing to Lloyd Harris on 16 March at the Dubai Duty Free Tennis Championships.
“I'm pleased with everything [in] my game,” said Thiem. “I’ve played three very different opponents. Everything is working quite well. [My] groundstrokes are working well. The serve was pretty good all the time. The return today, especially in some parts of the game, was very good.
“I guess that I'm on the right [path] definitely. But still many things to improve, getting 100 per cent back in the match rhythm, anticipation and everything… I am surprised to be in the semi-finals.”
Thiem will play fifth seed and 2018 titlist Alexander Zverev of Germany on Saturday.