The paradox of greatness in sport is champions are judged as much by their random shortcomings as their serial triumphs. Yet, when Rafael Nadal – the owner of 20 majors, most recently at his beloved Roland Garros for the 13th time – lost to Dominic Thiem in straight sets under the London lights, it was a glorious stumble against a superb opponent in one of the best matches of the year rather than a dispiriting defeat. He is not out of it yet but, at 34, Nadal’s 10th attempt to win the ATP Tour Finals on his least favourite surface will surely be among his last. The convoluted round-robin format may save him before the weekend but he had his chances against Thiem and could not close the show. The Austrian, who had looked drained after his opening three-set win over Stefanos Tsitsipas, was rejuvenated in his second appearance – against the player who has twice crushed his hopes in French Open finals. That was on their favoured clay; this battlefield, indoors hard-court, remains foreign in every way to the Mallorcan. “Definitely one of the better matches I have played in my career,” Thiem said of his 7-6 (7), 7-6 (4) victory. Both played their hearts out for nearly two and a half hours but, despite what viewers at home might have gathered from the “applause” that greeted every sumptuous winner, there were barely 50 people in the auditorium to witness it. What mattered more than showbiz noise was the integrity of their struggle. On an otherwise soulless afternoon, Nadal went 5-2 up in the first tie-break after an hour’s fierce combat and served for the first set before Thiem, who double-faulted at five-all, rediscovered his zest, standing up on his toes to smash a glorious winner across court. It momentarily shook Nadal and he was in trouble again when Thiem broke midway through the second. But he fought tigerishly against an onslaught of blindingly fast backhands to regain parity. He held to 15 to force another shootout but, in the continuing blizzard of excellence, it was Thiem who prevailed. It was his fifth winning tie-break in six against Nadal. “I played a little bit higher level even than at the US Open [his breakthrough grand slam],” Thiem said. “We both played great tennis. If we do, matches like that are the outcome. Very small things make the difference. Probably he was the better player in the first set and in the breaker, but I still won it. Rafa is 100% [switched on] from the first to the last point. So it was very important to get that first set, because he is almost impossible to beat if you lose the first set. “The second set had everything. I got the first break and played probably the best game of the match, then played another good tie-break. It was a great match, which I will remember for a long time.” He agreed his single-handed backhand down the line – one of the most exciting in the game alongside that of Stan Wawrinka and Roger Federer – worked perfectly on this surface, whereas it is rarely as effective against Nadal on clay. “I practised that shot so much before the season started again,” Thiem said. “That’s the only thing which is a little bit easy against Rafa on hard court or faster surfaces where the bounce is not that high. On clay, it’s impossible to do that shot against him. His topspin is way too aggressive. But here it’s faster. It’s not bouncing that high.” Nadal is used to fielding questions about his lack of success in indoor hard-court tournaments and his response is philosophically uniform. “It was a great match, decided by a few small details,” he said. “Well done to him. He played an amazing match – and I played well too. So my feeling is not negative. He had three match points but I had 5-2 in the first set and two serves in the tie-breaks. I am much more confident now with the level of tennis that I am playing than a couple of days ago.” On the unresolved subject of the Australian Open in mid-January, Nadal said: “There is a two-week quarantine but we can practise during these two weeks, so it’s not a big difference compared to what we are doing today. The only negative thing is we have to be there 16 days in advance. That’s the issue.” The bigger problem is whether or not the tournament will happen at all. Victoria’s Premier said this week it is far from a done deal, countering the confidence of the tournament director, Craig Tiley. Meanwhile, the ATP directors are meeting in London this week and their dilemma is stark: will 256 main-draw competitors not already in Australia, as well as a smaller army of hopefuls in men’s and women’s qualifying tournaments, be willing or able to get on to the dwindling number of very expensive flights to Melbourne from Europe and elsewhere? In the evening match, Stefanos Tstisipas prevailed after nearly two hours against Andrey Rublev, which put Thiem through to the semi-finals. That leaves the next match as a straight shootout between Nadal and Tsitsipas for the remaining place in that group. The Greek shot-maker won 6-1, 4-6, 7-6 (6) and there was suspense all the way to the end. In the 11th game of the deciding set, Rublev finished in a storm of brilliant shots before double faulting for 6-6. Serving at match point in the shootout, Tsitsipas was jubilant when the Russian dumped a routine forehand from the baseline. Rublev became the first player to be eliminated from the tournament.