Thibaut Courtois and Romelu Lukaku both played in the 2014 World Cup for Belgium and had key roles in their last-16 victory over the USA this time around. When the World Cup began 30 days ago, few believed Belgium - shorn of so many of the star names who featured in their previous campaigns on this stage - were among the potential winners. Even fewer would have believed it when they were 2-0 down with 85 minutes played against Senegal in the last 32.

But now the Red Devils are in the quarter-finals, having delivered one of the all-time great World Cup comebacks to vanquish the Senegalese, before following it up with one of the most impressive performances of the tournament so far in beating the USA 4-1 on their home turf. Eden Hazard, Mousa Dembele, Marouane Fellaini, and Vincent Kompany may be long gone, but a squad which still features Thibaut Courtois, Romelu Lukaku, Kevin de Bruyne and Axel Witsel has turned a mediocre start into a potential shot at glory.

As they prepare to take on Spain for a place in the semi-finals on Friday (20:00 BST), were the Belgian golden generation written off too soon, or is manager Rudi Garcia harnessing their power in a different way? Belgium reached the quarter-finals in Brazil in 2014 and then the semi-finals in Russia in 2018 - when their team was arguably at its peak - but were wretched in 2022, eliminated in the group stage behind Morocco and Croatia.

"I think this ​is a new era for us," Real Madrid goalkeeper Courtois, playing in his fourth World Cup, said before the USA victory. "It is true ​that there ⁠are some players from the golden era, but the World Cup in Qatar for us was ⁠not ​that good. "Now we have another generation with younger people, new people, willing to do great things and ​writing in the history pages for Belgium." And Courtois is right - the younger players are harbouring much of the burden.

Kevin de Bruyne scored his 38th goal for Belgium in the 5-1 group stage victory over New Zealand. Of the four survivors from 2014 and 2018, 34-year-old Courtois has played every minute of this tournament, but De Bruyne, Lukaku and Witsel have featured far less regularly. Central midfielder Witsel, 37, who left relegated Girona at the end of the La Liga season, was brought on for a single minute at the end of the win over the USA.

At 33, Lukaku has scored an impressive three goals but has done so by playing fewer than 50% of minutes, often coming on as a substitute and taking advantage of a tired defence reeling from the strong pressing of 25-year-old Atalanta forward Charles De Ketelaere. And De Bruyne, now 35, was injured during the Senegal game - before his departure Belgium had won one out of three matches, but since then they have won twice and scored seven goals in roughly 130 minutes of play.

Full-back Thomas Meunier also played in the 2018 tournament, but not 2014, and his minutes played have decreased as the tournament has gone on. None of that is to say the more senior players are not contributing - Courtois remains one of the world's best goalkeepers, Lukaku's goals have been crucial, and De Bruyne's performances were among the team's best before his unfortunate injury.

But their role in the squad is changing, with a greater reliance on them making the difference in key moments rather than taking responsibility for the overall quality of the team's performances. So far at least, Garcia and Belgium appear to handling the transition better than many teams do when their stars begin to fade.

Romelu Lukaku is Belgium's all-time leading World Cup scorer with seven goals across four tournaments. As far as Garcia is concerned, a focus on age is irrelevant and underplays the quality of players he has at his disposal. "I really can't stand it when my four leaders are called 'veterans'", he said earlier in the tournament. "It is ugly. It is awful. "If you are lucky enough as a country to have players of this calibre, then encourage them. This is what Belgium's 'old-timers' can do."

Their efforts have been aided so far by strong performances from some of those who were not around to bear the pressure of 2014 and 2018, but who have plenty of high-level experience of their own and play for some of Europe's leading clubs. Arsenal's Leandro Trossard has been particularly impressive, creating more chances (17) than any other player in the tournament, while he ranks 15th for goal contributions, with two goals and two assists.

De Ketelaere is not a prolific goalscorer but has scored two and assisted one while creating space for the wide attackers to play inside the penalty area more often. Hans Vanaken, a 33-year-old midfielder for Club Brugge, has never played outside Belgium domestically but has a goal and two assists to his name. And captain Youri Tielemans scored both the equaliser and winner against Senegal.

Of the 13 squad members aged 25 or below, perhaps only Manchester City winger Jeremy Doku could be considered an elite player, as things stand, although fellow wingers Diego Moreira and Matias Fernandez-Pardo have clear potential and Aston Villa's Amadou Onana played well before suffering an ACL injury against the USA.

Belgium appeared galvanised by the controversy over Fifa's decision to suspend USA striker Folarin Balogun's one-match suspension in the last 16. The players mocked President Trump by mimicking his campaign trail dance on the pitch, and afterwards Garcia praised the unity of his squad, saying: "The group is very mature. We have leaders to ​help us."

In the past, Lukaku has characterised himself as the more vocal of Belgium's leadership group, while De Bruyne sets professional standards in training on the pitch. One of the quirks of being a leader in the Belgium dressing room is language diversity. Belgium's colonial history and its modern position as the centre of the European Union make it highly diverse, and the World Cup squad features players with heritage from countries including DR Congo, Ghana, Guinea-Bissau, Senegal, France, Italy, Portugal, and Spain. Lukaku alone speaks six languages fluently.

Some players are native Dutch speakers from the north of the country, while some come from the French-speaking Wallonia region. Many speak both languages, but not all, meaning players commonly communicate in English as a group. "It's a very strategic thing to do", says Dr. Jim Ureel, senior lecturer in applied linguistics at the University of Antwerp. "Language is a very sensitive topic in Belgium - it's heavily linked to identity and politics. Dutch-speaking people don't necessarily want to adapt for the French, and vice-versa. If the players were choosing one or the other, it could become a problem. "English therefore becomes very useful - you can avoid those issues and it all becomes neutral, especially because young footballers almost always speak good English and lots play in English-speaking countries. "When things become more personal, in smaller groups, they might switch into what they're most comfortable with. "I think it's very clever how they do it."

If Belgium are to make it past Spain and beyond, Lukaku and his fellow leaders' motivational team talks are going to have to be especially inspirational, regardless of the language they're delivered in. This is not quite the golden generation having one last crack at fulfilling their potential, but rather a core of seasoned professionals taking on a new paternal role, leading forward those who are now their team-mates and will soon become their successors.