SEATTLE, June 16 (Xinhua) -- River Plate manager Marcelo Gallardo has moved to ease pressure on midfielder Franco Mastantuono ahead of the teenager's move to Real Madrid.

The 17-year-old will join the Spanish club in July after it triggered his buyout clause of 63 million euros (72 million U.S. dollars), making it the most expensive transfer in the history of Argentine football.

Speaking on the eve of River Plate's opening match at the FIFA Club World Cup against Japan's Urawa Red Diamonds, Gallardo called for calm and a football-first focus amid the global attention.

"I want to be very measured on this point," Gallardo told a news conference on Monday. "We're focusing on the football aspect and nothing else. We're letting the things that have already happened fall by the wayside and hoping that at this moment the team and Franco can experience this sporting event as naturally as possible."

Mastantuono has had a breakout season for River Plate with seven goals and four assists in 19 games across all competitions.

His performances earned him a call-up to Argentina's national team, and he became the youngest player to appear in an official match for the Albiceleste when he featured in a World Cup qualifier against Chile earlier this month.

Despite the intense spotlight surrounding Mastantuono's transfer, Gallardo said the young playmaker was not in danger of losing his focus ahead of Tuesday's clash at Lumen Field in Seattle.

"We have a big challenge, which is tomorrow's game. Talking about names and the transfer market... I don't think it's the right approach. We're only focused on tomorrow's game," he said.

"I'm going to continue managing [Mastantuono] as I have until now: as someone who has a desire to play football. The rest... and what comes from outside, we can't control. It's not that problematic or complex. He's here, he's fine, he's accompanied and his teammates are supporting him." ■