Kylian Mbappe will face his former teammates at Paris Saint-Germain for the first time since leaving the French club a year ago, as Xabi Alonso's Real Madrid revolution gets its biggest test yet in Wednesday's Club World Cup semifinal.

Mbappe should be remembered as a PSG legend, having spent seven prolific campaigns there, before departing as its all-time top scorer with 256 goals in 308 games.

But his legacy was somewhat tainted by the manner of his departure, with the sense among many that, for the few years of his time in Paris, he was just waiting for the right moment to move to Madrid, the club he had dreamed of representing since childhood.

PSG, under its Qatari president Nasser Al-Khelaifi, was not happy with the way in which Mbappe chose to run down his contract in order to sign for Real in 2024, denying the Parisian outfit a transfer fee.

A bitter legal dispute has gone on between the parties for much of the time since, with Mbappe claiming he is owed 55 million euros ($64.4 million) in unpaid wages and bonuses from his spell in Paris.

The latest twist came just this week, when one of Mbappe's lawyers told reporters that the France captain had withdrawn a complaint of moral harassment against his former employer.

That was after the Paris prosecutor's office revealed last month that an investigation had been opened following a complaint by the player over the way he was treated by PSG in the summer of 2023.

He believes he was sidelined by PSG and made to train with players the club was looking to offload after refusing to agree a new contract.

Mbappe missed a preseason tour to Japan and the start of the next campaign, before eventually being reintegrated into Luis Enrique's squad.

All of that should have been behind Mbappe long ago, given the way his first season at Real has gone on a personal level.

The 26-year-old, a World Cup winner in 2018, scored 43 goals in 56 matches for his new club across all competitions up to the end of the La Liga campaign, a remarkable tally.

However, Mbappe has endured frustration at the Club World Cup, not featuring at all during the group stage due to a stomach bug that led to him requiring hospital treatment.

First start?

In his absence, young forward Gonzalo Garcia has made the step up to the senior side in impressive fashion, starting all five matches in the United States and scoring four goals.

The last of those was the opener in the 3-2 quarterfinal win over Borussia Dortmund at the MetLife Stadium on Saturday, but it was Mbappe who scored what was, ultimately, the deciding goal.

He came off the bench midway through the second half and scored a brilliant, acrobatic overhead kick in stoppage time for Real's third of the afternoon.

"He is still not perfect, not 100 percent, but he is getting better every day," Alonso said of Mbappe after that match.

"Now he will have three days to keep progressing and feeling better ahead of the semifinal."

It is hard to imagine Mbappe not getting his first start of the tournament against PSG, the club that won the Champions League in the season following his departure after so many years of disappointment in Europe with him in the team.

PSG came to the US fresh from crushing Inter Milan 5-0 in the Champions League final.

It reached the last four with a 2-0 quarterfinal win over Bayern Munich in Atlanta — despite having Willian Pacho and Lucas Hernandez sent off — and need not fear Real.

"It doesn't matter who we play in the semifinals," said Enrique, for whom this is also a special occasion, given that he spent five years at Madrid as a player in the 1990s.

"All that matters is that we are there, and that we want to get to the final."

Alonso has just taken over as Real coach after an outstanding spell with Bayer Leverkusen, and has already displayed great tactical flexibility, flitting between a back four and a three-man central defense at the tournament.

It will be fascinating to see which system he opts for here, and if Mbappe starts, as the striker prepares to play against PSG for the first time since July 2017, when he was still a thrilling teenager at Monaco.

AFP