(Reuters) - Belgium departed the World Cup on Saturday with a sense of unfinished business but also having set out a marker for future tournaments, notably the next European Championship in 2016 and the 2018 World Cup.

Their 1-0 quarter-final loss to Argentina was a heart-breaking experience but with a relatively youthful squad - the third youngest of the 32 teams at the World Cup with an average age of 25.5 years - Belgium have the potential to develop into a force to be reckoned with.

"We are now inconsolable but we can look back on a good tournament," coach Marc Wilmots said moments after the final whistle sounded on their participation in Brazil.

Participation in the World Cup ended more than a decade without an appearance at a major tournament for Belgium and will have given the squad a major dose of self-belief.

But the Red Devils need to reflect on a tournament in Brazil where they made heavy work of their opponents at times and find the reason why their talisman Eden Hazard failed to spark.

There were only glimpses of the potential of the skilful midfielder, whose role on the left was overshadowed by the outstanding workman-like attitude of Kevin de Bruyne on the right.

Hazard seemed to struggle with stage fright at times and did not come remotely close to his potential.

The Belgians might also have imposed themselves more in the first round, although they can point to a perfect haul of nine points from three matches and an opportunity in their last Group H game.

NARROW VICTORY

They ran the United States ragged in the last 16 but after missing many chances were forced to hang on for a narrow extra-time victory.

Apart from De Bruyne, there were other impressive individual performances.

Axel Witsel's calm, steady and no-frills approach in midfield sees him leave with an enhanced reputation and captain Vincent Kompany was an impressive leader, even though he struggled with a groin injury.

Giant goalkeeper Thibaut Courtois is also among the many reasons for Belgian optimism about the future.

"We can leave with our heads high and now think about the future," he told reporters.

Center back Daniel van Buyten, probably at the end of his international career at the age of 36, made more blocks than any other player in the group phase, according to statistics.

His contract with Bayern Munich is at an end but, despite his advanced years, he would certainly have attracted the interest of many club managers who could see a role for him this coming season

Wilmots's surprise choice of teenager Divock Origi for the tournament proved inspired. On Saturday the 19-year-old became the youngest player in a World Cup quarter-final starting line-up since Pele in 1958.

"We did our best and that is the most important. Our young team knows there are more World Cups to come. Maybe in four years in Russia we'll have a better chance," Kompany said.