Juve's McKennie, a rare American making waves in Serie A

The 22-year-old Texan became the first player from the United States to play for the Turin giants when he arrived from Bundesliga club Schalke last summer on loan.

Coach Andrea Pirlo has hailed the young international as "a rock" in a difficult period for the Italian champions with an ongoing injury crisis.

Juventus trail Portuguese club Porto 2-1 going into the second leg of their Champions League last 16 tie in Turin on Tuesday.

Forward Chiesa, 23, pulled a goal back for the Italians late in Portugal, for a precious away goal as they look to avoid crashing in the last 16 for a second consecutive year.

McKennie helped Juventus out of the group stage with a goal in a 3-0 win at Barcelona in December having lost the home leg 2-0.

It was the second Champions League goal for McKennie having previously scored one for Schalke.

The Italians have won the European title twice, but not since 1996, and Pirlo warned that the Porto game was a "decisive match we can't mess up".

McKennie has found his feet in northern Italy and his move from Schalke was made permanent on Wednesday, Juve buying him outright for 18.5 million euros ($22.3 million) on a deal until June 2025.

"We chose him for his characteristics, we followed him," said Pirlo.

"Now that he has been bought outright he can't think that he's arrived; this is a starting point.

"If he thinks he has reached the top he has made a mistake and is not on the right path."

There have only been a handful of Americans who have played in Serie A over the years, such as Michael Bradley at Chievo and Roma, Armando Frigo at Fiorentina and Alexi Lalas at Padova.

"You grew up watching these players, idolising them and playing them on video games and now they're your teammate, it's a dream come true," said McKennie on playing alongside the likes of Cristiano Ronaldo.

- 'Grits his teeth' -

Despite niggling injuries and catching coronavirus in October, McKennie has remained a reliable option for the Serie A champions, scoring five times in 32 appearances.

"McKennie is also not 100 percent fit, he has a hip problem, but he is a rock and he grits his teeth because we haven't got many players available," said Pirlo after the Porto defeat.

That loss in Portugal came after falling to Napoli in the league.

Since then, Juventus have gotten back on track in Serie A with 10 goals in four games, consolidating third place with a 3-1 win over Lazio at the weekend.

McKennie's performances for club and country, where he scored the quickest hat-trick in US men's soccer history with three goals in 13 minutes in the CONCACAF Nations League in 2019, saw him voted the best American male soccer player of 2020.

"It's a big deal, I remember when I was in the U17 and I wasn't even considered in the U17 World Cup or qualifiers," McKennie told former US captain Carlos Bocanegra on hearing he had won the award.

"To get to this point, it's a big, long journey for sure."

McKennie spent part of his childhood in Germany where his father worked with the United States Air Force at the Ramstein Base near Kaiserlautern.

He joined FC Phoenix Otterbach in 2004.

On his return to the US, McKennie played for Major League Soccer side FC Dallas' youth team for seven years before moving to Schalke in 2016.

- First trophy -

For Schalke, McKennie made 91 Bundesliga appearances, scoring five goals.

Pirlo's arrival, which came when Maurizio Sarri was sacked after more Champions League disappointment, heralded in a wave of younger players.

McKennie arrived along with Barcelona defender Arthur, 24, with veterans including Miralem Pjanic, Gonzalo Higuain and Blaise Matuidi all leaving.

Swede Kulusevski, 20, signed from Parma, scoring on his professional debut, with Chiesa, 23, arriving on loan from Fiorentina.

Spanish striker Alvaro Morata, 28, returned to Juventus where he played with Pirlo from 2014-2016.

Juventus have scored a total of 36 goals in all competitions from new signings.

Morata has scored 16, including six in the Champions League, Chiesa nine, McKennie and Kulusevski five each and Arthur one.

"Words can't describe the feeling of finally being able to raise a trophy," said McKennie on claiming his first trophy in the Italian Supercup, adding he hoped "it will be the first of many."