MONACO — An intriguing battle lies in store between arguably best the attack and the toughest defence in European football when Monaco faces Juventus in the first leg of their Champions League semifinal on Wednesday.

Monaco has been scoring freely all season, with 146 goals so far. But coach Leonardo Jardim now faces a more difficult challenge in how to approach the game.

"I'm always optimistic," Jardim said Tuesday. "If the coach isn't optimistic, he can't get his message across to the players."

In the previous knockout rounds, Jardim had a specific plan to impose his style of play against both Manchester City and Borussia Dortmund — teams rich in attacking promise, but wide open at the back.

"Juventus is totally different from the other teams," Jardim said at a pre-match news conference. "We need to pay closer attention to their transition play and attack them very quickly, because it's very hard to get inside their penalty area."

So confident was Jardim in his attacking play in those other knockout matches that he even announced in pre-match news conferences what was required to go through.

"They've scored an avalanche of goals this season," Juventus goalkeeper Gianluigi Buffon said Tuesday through a translator. "I have total respect for Monaco and whatever happens tomorrow it will be open for the return leg."

Monaco's attack has pace, skill and power, and passes the ball at thrilling speed. But so did Barcelona's, and the five-time champion failed to score in either leg of its quarterfinal defeat against Juventus.

"Experience will be more in our favour, but Monaco is a young side full of vitality," the 39-year-old Buffon said. "I remember having this great feeling of being indestructible when I was young."

Buffon accepts the pressure is on Juve.

"Two years ago, when we reached the final against Barcelona, it was unexpected," Buffon said. "But this season it would be a logical conclusion to the work we've done."

The sides met two years ago in the quarterfinals, with Juventus edging through 1-0 on aggregate. But this is a far more adventurous Monaco side.

"Jardim's done an extraordinary job, semifinal in the Champions League and top of the French league ahead of PSG," Juventus coach Massimiliano Allegri said. "Monaco breaks forward very quickly."

Jardim, however, may have to adapt his team to an opponent this time, rather than taking the initiative. This poses a huge test of the Portuguese coach's tactical shrewdness, and the ability of his highly-rated forwards to break down the Juventus rearguard.

"I don't think Monaco will change the way it plays," Buffon said. "Monaco has been brilliant this season and plays a brand of total football that is great to watch."

Monaco's teenage striker Kylian Mbappe has been earning rave reviews after scoring in each of the four knockout matches so far, and his partnership with Colombia striker Radamel Falcao has produced 52 goals.

But theirs is a nascent partnership, and together they have not faced defenders of the calibre of Leonardo Bonucci and Giorgio Chiellini: a formidable centre half pairing in Italy's national team and Juventus teammates for seven years.

Hard as nails, uncompromising, tactically astute and solid in the air — not much gets past this partnership. Barcelona's Lionel Messi couldn't add to his tournament-leading 11 goals against them.

The 30-year-old Bonucci, who joined Juventus in 2010, is more skilful than most centre halves, giving the team an outlet with his excellent passing.

The 32-year-old Chiellini, who has been at the club since 2005, is a rugged man-marker and far stronger in the challenge.

Italy's 168-cap veteran Buffon is arguably still the best in the world.

Add former Barcelona livewire Dani Alves at right back, and veteran Andrea Barzagli — when the 35-year-old centre back is required — and you have an experienced and solid defence that any coach would dream about.

The attack-minded Alex Sandro has meanwhile proved himself to be a reliable left back since arriving from Porto last season.

Allegri's side has only conceded 22 goals in 34 league matches and two in 10 Champions League games. Juventus remains on course for the treble, opening up a nine-point lead over Roma with four games left in Serie A and reaching the Italian Cup final.

But Allegri also has a prolific attack, with Gonzalo Higuain — the club's record signing for 90 million euros ($100 million) —and Paulo Dybala. Dybala netted two fine goals against Barcelona, while muscular Croatian forward Mario Mandzukic will give Monaco's vulnerable defence nightmares on set pieces.

"Juventus has a strong winning culture and is so strong and organized in defence," Jardim said. "Going forward, they don't need many chances. They're especially dangerous on corners and free kicks because of their experience."

For Jardim, the target will be to at least outscore Juventus in order to have some kind of safety net away. Especially considering Juventus has not lost at home in the Champions League for four years.

In previous knockout rounds, Monaco was away first — applying significant pressure with three goals at City and Dortmund.

Now it's time to see if Monaco can apply the pressure on Juventus.