Aston Villa beat Bologna in the Europa League quarter-finals to set up a semi-final against Nottingham Forest.

Aston Villa's squad are entering a defining moment under manager Unai Emery. Trailing 1-0 going into Thursday's Europa League semi-final second leg against Nottingham Forest (20:00 BST), a 30-year trophy drought hangs around the club's neck. There is a growing sense it is this squad's last chance to end it.

Nine of the current squad started Emery's first game - a 3-1 win over Manchester United in November 2022 - with John McGinn and Boubacar Kamara coming off the bench. Six of those players started against Forest last week, Villa suffering a first-leg defeat.

Stability has underpinned Villa's success under former Arsenal boss Emery, who took over when the club were 14th and three points above the relegation zone. But as they stumble just before the biggest game of his reign, has Emery taken this group as far as he can?

Villa's wretched 2-1 home defeat by Tottenham on Sunday - a third consecutive loss - did not give them the ideal platform, even if Emery made eight changes. It underlined the lack of depth within the squad, with Emi Martinez, Matty Cash, Youri Tielemans and Morgan Rogers viewed as the only first-choice starters in Sunday's XI.

Emery, though, has earned admiration from at least two fellow Premier League managers who have been privately impressed with the decisions he made - a clear focus on his biggest game at the club - and how he stuck to the strategy. He has won the Europa League a record four times - three times with Sevilla and once with Villarreal - and with minds focused those close to Emery expect to see a different performance to Sunday's surrender.

"We are improving, including myself, and we will have more challenges to set for the present or future," said Emery, when asked if this is the last chance for this squad to win something. "I don't think tomorrow is the last opportunity for us or anyone. The players are enjoying the process we are doing and they are aware about how difficult football is, and this is the greatest moment we are having in the last three years.

"It will break nothing about how we are thinking and trying to improve." Even if Emery believes they can push for honours beyond this season and with Champions League football - Villa should finish in the Premier League's top five regardless of their European fate - changes are expected.

The squad needs to be refreshed and selling players is the easiest way to comply with regulations - with England forward Morgan Rogers their biggest asset. There is a realisation a significant number need to be recycled and Emery has been aware since the opening month of the season what needs to be done.

He and president of football operations Roberto Olabe are aligned, but Olabe was brought in to help progress Villa further, more medium and longer term. Going forward there will be more focus on younger players, and filling the necessary first-team gaps with more senior signings, but Emery, the same as any manager, wants players who are ready now.

The pair are close - Emery handpicked Olabe to replace Monchi in September - so a common ground is found and the duo spend hours talking about tactics and philosophies, conversations which usually start in the club's canteen at Bodymoor Heath.

Yet the desire for new players to take Villa to the next level is the hardest task. Douglas Luiz has made 219 appearances during his two spells at Aston Villa. The squad has likely reached its limit and there appears to be a gap between the expected core of 13 and the rest, but to sign players who will really improve the group costs money.

It is why Villa re-signed Douglas Luiz on loan in January. The midfielder has failed to impress at Juventus, and during his loan spell at Nottingham Forest this season, but knows Emery's methods.

Spending restrictions mean the club have had to work carefully as they aim to comply with profit and sustainability rules (PSR), both the Premier League's and Uefa's - having been fined by the European governing body last year. Villa feel there needs to be regulation, but believe the different spending rules do not complement each other.

To do that, Luiz was initially sold to Juventus after Villa reached the Champions League two years ago, and last summer Jacob Ramsey left for Newcastle for £40m. Villa do not want to spend the £35m to make Harvey Elliott's loan from Liverpool permanent, with the attacking midfielder stuck on nine Premier League appearances - one short of triggering a deal. Elliott is one of those players deemed not good enough for the price.

Although, how Emery and Villa revamp the squad remains up for debate until their Champions League fate is known. Then the market will dictate, and Emery may be required to work some more magic.

"When I arrived here three and a half years ago, it was a dream to be playing a semi-final of the Europa League," said the Spaniard. "Finishing the season like we are now, in the league and in a semi-final, it's really something fantastic."

Striker Ollie Watkins has already hinted the squad expects changes. Tyrone Mings, McGinn and Tammy Abraham - during his loan from Chelsea - started when Villa beat Derby in the Championship play-off final in 2019. Ezri Konsa and Luiz joined that summer, while Watkins signed a year later for a then record £28m from Brentford, along with Cash and Martinez.

Emery has moulded many from Championship players into Champions League contenders from a squad which previously had not finished higher than 11th since returning to the top flight and were floundering under predecessor Steven Gerrard. But all good things come to an end.

"Squads change every year and players always leave," said England forward Watkins. "This is the only moment when we will have all of the same players in the dressing room this year. We need to do everything we can to get to the end.

"The team is pretty much the same as when Dean Smith was here, apart from a few good additions. We can always count on each other and it is nice to have a core that has been together for numerous years. It is quite rare."