Kylian Mbappe is fully under contract with Paris Saint-Germain as of Sunday, after his permanent deal with the French champions kicked in on the first day of July.

The 19-year-old was on loan from Monaco last season, when he scored 13 goals and provided seven assists in 28 Ligue 1 appearances. PSG were obligated to buy him for €180 million once they officially avoided relegation.

That clause was activated in mid-February, and since then, Les Parisiens knew that they would be committing mega-money to sign a star talent for the second consecutive summer, after last year's €222m purchase of Neymar from Barcelona.

Celebrating his first day as a full PSG player, Mbappe is now under contract until 2022 and is the French capital outfit's second-highest earner behind Neymar.

Mbappe scored two goals on Saturday to help France beat Argentina in a spectacular 4-3 win in the World Cup round of 16, prompting an explosion of praise for the teenager.

Mbappe now has three goals from as many starts to his name in Russia this summer, while he is also the first French player to have scored at least two goals in a World Cup knockout game since Zinedine Zidane's double against Brazil in the 1998 final.

France's Kylian Mbappe Catherine Ivill/Getty Images

As well as becoming the youngest player -- at 19 years and six months -- to score two goals at the World Cup since England's Michael Owen (18 years, six months) in 1998, Mbappe is now the youngest player to score at least two goals in a World Cup match since Pele against Sweden in 1958, when he was just 17 years and eight months.

The Brazilian legend even took to Twitter to congratulate Mbappe on his accomplishment and wish him luck for the remainder of the World Cup.

"Congratulations, Kylian," wrote Pele. "Two goals in a World Cup so young puts you in great company!"

Meanwhile, France teammates Florian Thauvin and Antoine Griezmann had plenty to say about the PSG man in Sunday's news conference in Istra.

"I call him 37 now," revealed Thauvin. "Because he clocked in at 37 kilometres per hour and I had to ask myself if he was on a scooter or not!"

But Griezmann warned: "Do not expect the same thing in the quarterfinals. [Uruguay] saw the match. Kylian's speed, how calm he is... He is 19 and the guy is so calm before taking to the pitch -- it is up to us to help him.

"He listens, he likes the one-two and technical stuff. When he is in the mood to inflict hurt, he is and will be a top player. The focus on Kylian will not change anything. I am here to win. If Kylian keeps scoring braces, we will keep progressing.

"There are many nicknames [for Mbappe], and even though Kylian does not like 'Kyky,' I think that it will stick."