Belgian football's hopes are high that a generation of hard work in rebuilding from the grass roots will bear fruit at this World Cup, but coaches are already looking beyond and at how to outfox bigger rivals next time.
- There have now been nine 90th minute winning goals in the 2018 World Cup.
Trailing 2-0, Vertonghen scored with a header in the 69th minute that appeared to be a cross but somehow dropped in under the bar.
Belgium have not kept a clean sheet in their 12 World Cup knockout-round matches, shipping 28 goals.
"It was a test of character and you see the reaction of our subs coming on to win the game", he said.
Belgium won all three Group stage games and outscored their opponents 9-2 in the process.
Belgium's chances of making the last eight looked far more remote in the 52nd minute, however, when Takashi Inui lashed home Japan's second shortly after Genki Haraguchi had opened the scoring.
'But it's a game that when you are a little boy you dream of - playing against Brazil in a World Cup quarter-final.
Japan narrowly scraped through, advancing ahead of Senegal because it had fewer yellow cards.
"Credit to Belgium - at 2-0 down they were out of this competition".
Pre-tournament favourites Brazil were held by Switzerland and struggled to overcome Costa Rica in the group stage, but impressed in the second half of their last-16 win against Mexico.
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He was unable to inspire Spain to victory however as they were beaten 4-3 on penalties by the World Cup hosts. We will be back at big tournaments again.
"I told the players to go and take a shower because they were just standing there not able to do anything", said a dejected Nishino after Nacer Chadli's victor deep in stoppage time from a lightning quick counter attack after a Japan corner.
Akira Nishino's side were tactically outstanding, though, containing their attacking threat perfectly.
Yet Nacer Chadli had other ideas, the substitute applying the finishing touch to a textbook counter-attack in the fourth minute of stoppage time to send the Belgium fans into delirium.
Yes, ultimately, Japan failed to hold on to a two-goal lead and some one would even label their adventurous approach in the final seconds as naïve.
Japan had never scored a goal in the World Cup's knockout rounds but they ended their wait in the 48th minute through Haraguchi. Marouane Fellaini then came to his team's rescue, nodding home to bring the scores level after a brilliant cross by an otherwise ineffectual Eden Hazard.
Although Honda had his moments of brilliance, he largely played the role of impact substitute, while Okazaki - for so long the lone tireless toiler up forward - was only afforded 68 minutes in total.
In four years' time, it will be this brigade that spearheads another Japan bid to reach their maiden quarter-final appearance and they will do so with the experience of having come so close on this occasion.
There was also 25-year-old Gen Shoji, still plying his trade in the J1 League with Kashima Antlers but who did not look out place battling it out with Lukaku and Radamel Falcao.
And there is still plenty more talent to come through with Takuma Asano, Shoya Nakajima, Yosuke Ideguchi and Kenyu Sugimoto just some of those waiting in the wings.
It will be Martinez's job to address the weaknesses, to ensure they don't make similar mistakes in their quarterfinal.