Questions will be asked of Chelsea and coach Sonia Bompastor if they do not emerge as Women's Champions League contenders by next year, believes Lianne Sanderson.

The Champions League trophy evaded Chelsea throughout 12 successful years under former boss Emma Hayes, who left to coach the United States national team last May.

Hayes won 16 domestic trophies with the Blues, including seven Women's Super League titles, but a 4-0 final defeat to Barcelona in 2021 was the closest her team got to European glory.

And it looks as though the same opponents will deny Chelsea once again, with Barca winning 4-1 in the first leg of a Champions League semi-final last week.

Chelsea must now overturn a three-goal deficit at Stamford Bridge on Sunday, against a Barca team that has progressed from five straight semi-final ties.

Bompastor's first season has been hugely successful, with Chelsea closing in on the title in the league, in which they are unbeaten, and into the FA Cup final.

They also captured the League Cup with a 2-1 victory over Manchester City last month, so they could win the domestic treble for just the second time after doing so in 2020-21.

But former England international Sanderson, who played for Chelsea between 2008 and 2010, thinks they need to take the next step soon.

She told Stats Perform: "When Emma Hayes was there, every year it was like they were in for a quadruple, they were in for the treble, then it went down to the double, then they won the WSL. 

"It's still a successful season if you win the league, but let's be honest, Chelsea haven't bought in Keira Walsh and Lucy Bronze to win the league, and [Sandy] Baltimore and Naomi Germa. 

"They haven't bought them in to win the WSL, they do that anyway, they've bought them in to win the Champions League."

While Sanderson accepts the pressure of following Hayes was immense, she believes Bompastor – a Champions League winner as both a player and a coach at Lyon – must deliver more next season.

"I think if it's this time next year and they're in the same position, then questions will be asked," she said.

"Sonia Bompastor has done a really good job in a short space of time. I don't think anybody realised what was going to happen upon Hayes leaving. 

"You're talking about the equivalent of [Jurgen] Klopp leaving, or Sir Alex Ferguson. 

"Chelsea this year, apart from the two draws they've had in the league, they've not been playing well but they're still getting the results. That is the testimony of a great team."

While Chelsea have been dominant in the WSL and could complete just the fourth unbeaten campaign in the competition, having themselves avoided defeat in 2017-18 and 2019-20 (also Arsenal in 2012-13), Sanderson thinks their team can sometimes look unbalanced.

"I think they have too many good players, if that's even possible. I think Bompastor needs to find the balance," she said. 

"Chelsea were on the back foot from minute one [against Barcelona]. Hopefully I'm standing here next week and asking why Chelsea are in the final, but if I was a betting person, that's not what I'd be betting on."