Marquinhos on Luis Enrique's Ruthless Standards in Training

Marquinhos has laid down the law: under Luis Enrique, there is nowhere to hide.

On the eve of their continental campaign, the Brazilian defender spelled out just how ruthless life has become under the Spanish coach. Train at full tilt, every day, or be prepared to disappear from the squad.

"He's not just making tough decisions this season. He has his own way of managing. The group has to give 100% in training to earn their place. That's what he demands," Marquinhos said, lifting the lid on the standards now expected.

The message inside the dressing room is blunt. Reputation no longer guarantees a shirt. Effort does.

"It's up to the players to push themselves to the limit every day. Everyone has to work to earn their place in the group," he continued. "Sometimes players are left out of the squad. That hurts, but everyone understands. That's football, that's how it is. He's done a very good job managing so far, it's worked. He has his philosophy and he's not afraid to make tough decisions when necessary."

Those decisions are backed by a heavyweight European résumé. Enrique walks into this Champions League campaign with a 63 per cent win rate in the competition, the best of any coach to have taken charge of at least 50 matches. That kind of record gives authority to every demand he makes.

And he is already warning against any hint of complacency as Slovakian opposition arrive for the opener.

"This is the toughest competition. How many teams can win? Six, eight, five. The difference is very small. We're aiming for a very good start," the coach said, sharply cutting through any talk of a gentle introduction. "We're going to play a seemingly easy match, but there are no easy matches. We have to stay focused."

The standards are clear. The margin for error, in training or under the floodlights, is not.