After the polemics over toilet breaks and the public slanging matches about professional ethics, and with a week of struggling to stay within contact of the climbing specialists behind him, Tom Dumoulin finally became the first Dutchman to win the Giro d’Italia, but the doubt in his mind lasted until the final rider in the field reached the last of the 3,612 kilometres.

When Nairo Quintana passed under the red kite marking one kilometre to go in Sunday’s time trial from Monza to the centre of Milan, the clock said the pink-jerseyed Colombian needed to cover the final 1,000 metres in 59 seconds if he was to prevent Dumoulin from overhauling him and taking victory. With several tight bends leading into Milan’s Piazza Duomo, that was clearly unfeasible.

At that point Dumoulin, sitting in a tent by the finish having completed his race 10 minutes earlier, was finally able to overcome his nerves and smile. He eventually ran out the winner by 31 seconds, having overturned Quintana’s overnight advantage of 53 seconds to leap from fourth overall to first. So ended one of the closest fought of cycling’s three Grand Tours in recent years, with Vincenzo Nibali and Thibaut Pinot also starting the day as possible winners, both within 43 seconds of Quintana.

“It was such a nerve-racking day. I was so nervous,” said Dumoulin. “I knew I need to stay calm but I couldn’t.” This was also the high point of a rise that has taken two and a half years, since he took bronze in the world time trial championship in Ponferrada behind Sir Bradley Wiggins and the German Tony Martin; last year he added two stages in the Tour de France, including a win on a rain soaked mountain top in Andorra which now looks like something of a milestone.

This was a first for Holland but winning any of the three-week Tours is, paradoxically, a rare achievement for one of Europe’s leading cycling nations. Prior to Dumoulin, only Joop Zoetemelk and Jan Janssen have managed the feat for Holland, taking one Tour de France and one Vuelta each, but there has been a 37-year drought at this level for the Dutch since Zoetemelk’s 1980 Tour win.

The die was cast soon after the start on the Monza motor racing circuit, with Dumoulin 31 seconds faster than Quintana at the first time check after 8.8km. That suggested he would take the final pink jersey, but not by a great deal; nine kilometres later, on the outskirts of Milan at Sesto San Giovanni, Quintana was timed one minute slower, his lead lost but by no means conclusively.

The final week’s racing had been fought out with this time trial in most minds. The consensus was that Quintana needed to start with a margin of two minutes over Dumoulin to be certain of holding him off; after the Dutchman’s stage win last Saturday at the Oropa Sanctuary the Colombian had been 2min 49sec back, with Pinot and Nibali further behind. The maths was simple; they all needed to gain between five and six minutes on Dumoulin. History suggested that could happen, as Dumoulin had cracked at the very end of the 2015 Vuelta a España, losing the red jersey on the final mountain stage. But here it proved impossible. The twin ascents of the Stelvio Pass on Tuesday were the climbers’ best chance; although Dumoulin did cede time there, and on Friday’s brutal stage to Piancavallo, and on Saturday at Asiago, on each occasion he managed to limit his losses by letting Quintana, Pinot and Nibali go ahead, then riding at his limit without ever pushing himself to breaking point.

That sounds simple but it takes self-discipline and a cool head to avoid the obvious temptation to push just a little bit harder. Moreover he managed it without the help of his key mountain domestique Wilco Kelderman, who was eliminated in the same crash that put out Great Britain’s Geraint Thomas and which reduced Adam Yates’s race to a courageous bid for the white jersey for the best young rider, which lasted until Milan where he was pipped by Luxembourg’s Bob Jungels.

The four-way battle between the three climbers and the time triallist set up a finale that did not quite provide the closest ending to a Grand Tour ever – the 1984 Vuelta was won by six seconds, the 1989 Tour de France by eight seconds – but was enthralling largely because the destiny of the race could have been decided by a puncture, crash or a moment of weakness.

In the last few days even the men at the top of the standings had looked out on their feet and that was confirmed on the road to Milan. Dumoulin looked imperious, his style and rhythm perfect compared with Quintana’s more cramped position, but he was not fresh enough to win the stage – that honour went to his fellow Dutchman Jos Van Emden – and he was nowhere near as incisive as he had been in either of his stage wins at Montefalco and at Oropa.

His final margin of 31 seconds sounds adequate but that amount of time can be lost in the final kilometre of any mountain if hunger-knock strikes, or at the end of a flat stage through a crash or a relatively minimalsplit in the field. To have won the Giro by a single second, all Quintana would have had to do was dislodge Dumoulin by 22 seconds and add a 10-second time bonus for winning a stage. In that context the Dutchman won by next to nothing.