The 40 million pounds signing from Manchester United has started just two of seven Premier League games since Rosenior's arrival, with a tactical shift to dominate midfield areas limiting Chelsea to one winger at times. But with Pedro Neto suspended and other wide options sidelined, Garnacho is in line for an opportunity.

"Garna is a top player," Rosenior said. "I've changed a little bit tactically since I've come in; I've wanted to dominate midfield areas. That has meant at times I've only played with one winger, but Garna is an outstanding player.

"What I've really liked in this period is his reaction to not starting. He's been training very well and showed real positivity when he came on against Arsenal. He was also magnificent against Hull in the FA Cup and had a huge impact in the game against Arsenal when he scored two goals."

The winger's cameo in the 2-1 defeat to Arsenal nearly earned a point, and Rosenior believes his response behind the scenes has been just as important.

"We have got to take into account that Garna is 21 – he's got huge ability and huge potential," he said. "For any young player, the biggest thing to be challenged is your consistency level, but he's showing really good signs, not just in training but in meetings, that he's on a really good track. He's definitely going to get his opportunities with the schedule we've got coming up."

Rosenior added: "I want to find out about people's character not just when times are good, but when times are difficult as well. What I want is a consistent winning team, and to have that you need consistent behaviours and habits regardless of what's happening to you individually.

"So not just Garna, every player knows from the conversations I've had that how they operate day to day affects my team selection. And Garna has put himself in a really, really good place the last few weeks and he's more than knocking on the door to start."

The Chelsea boss also defended Garnacho over the treatment he receives from opposition supporters.

"I don't understand. I don't understand why that happens," Rosenior said. "Maybe it's because he can be such a threat. Playing for a club like Chelsea, that just comes with the territory. You have to rise above that.

"Opposition fans booing you normally means you're a threat. All Garna needs to do is keep working really hard because his ability is not in question."

Rosenior revealed the winger recently dealt with a personal issue but still made himself available for selection.

"He's had a very difficult thing happen in his life recently as well. And rather than tell me about that, he wanted to put himself forward for a game and told me after.

"People make judgments based on the way people look. Garna is a really, really good character who works really hard every day in training and I know in the end his quality is going to show in a really consistent way."

Asked whether Garnacho is sometimes guilty of diving, Rosenior replied: "No."

With Chelsea six points adrift of Villa in the race for Champions League qualification and a last-16 clash with holders Paris Saint-Germain on the horizon, Garnacho may now have the platform to turn Rosenior's faith into a sustained run in the side.

Liam Rosenior: 'Outstanding' Alejandro Garnacho will become long-term Chelsea success