After a series of painful Champions League failures, Pep Guardiola is on a mission to seal his Manchester City legacy by finally getting his hands on the trophy again.

City start their latest bid to win the club’s first European Cup with a trip to Shakhtar Donetsk in the Group C opener on Wednesday.

The long flight to Ukraine will give Guardiola plenty of time to ponder his curious streak of Champions League flops in recent years.

Guardiola has conquered English football spectacularly after winning the last two Premier League titles, the first in record-breaking fashion and the second as part of an unprecedented domestic treble last season.

Yet the Champions League has proved impossible for Guardiola to master since he arrived at the Etihad Stadium.

In fact, Europe’s elite club competition has been a cruel mistress for Guardiola for most of the last decade, with a series of frustrating exits during his spells in charge of Barcelona, Bayern Munich and City.

Guardiola first won the Champions League as a manager in 2009 with Barcelona.

But he has failed to reach the semi-finals in any of his three seasons as City boss, extending his long wait to win the tournament for the third time — his second triumph coming with Barca in 2011.

City’s best Champions League run was under Guardiola’s predecessor Manuel Pellegrini, who made the semi-finals in the last season before the Spaniard took over.

And Guardiola’s inability to win the Champions League without Barcelona superstar Lionel Messi in his team is a black mark his critics use to question the 48-year-old’s right to be ranked as a managerial legend.

While that assessment is harsh on the innovative and inspirational Guardiola, his European campaigns with City have undoubtedly been painful experiences that exposed the few flaws in his team.

VAR was the scapegoat for last season’s dramatic quarter-final defeat against Tottenham, but the real reasons for City’s failure to progress were a subdued first leg performance in north London and a defensive meltdown in the second leg.

The year before that Liverpool punished City’s oddly timid display quarter-final display at Anfield, while Monaco shockingly eliminated Guardiola’s side after an error-prone last 16 tie in his first season.

With five Champions League semi-final defeats on his CV — two with Barca and three with Bayern — Guardiola has become the competition’s nearly-man since 2011, when his Messi-inspired team delivered a masterclass in the Wembley final against Manchester United.

That memorable evening stands as Guardiola’s last fond memory of the tournament and the clock is ticking on his hopes of winning it for the third time.

There is the looming prospect of UEFA sanctions, with City potentially facing a Champions League ban from the ongoing investigation into their adherence to financial fair play regulations.

Worryingly for Guardiola’s hopes of lifting the famous ‘cup with the big ears’ in Istanbul later this season, City have endured a rocky start to the new Premier League season.

They are already five points behind leaders Liverpool after Saturday’s surprise 3-2 defeat at Norwich, a result that showed how badly City will miss injured centre-back Aymeric Laporte.

At least City have what looks on paper a relatively undemanding group, with Atalanta and Dinamo Zagreb their other opponents.

Guardiola remains adamant his players will steer City back to calmer waters even without Laporte.

“If today you believe I have doubts in my team because we lost a game…They gave me all the prestige I have in England,” he said after the Norwich game.

“In the first season, it was ‘fraud Guardiola, Fraudiola’. OK, and how it was not possible to play this way because you have too many tackles.

“It was these players who gave me the prestige I have all round the world about how good a manager I am.”

Guardiola, Fraudiola vow to bring Manchester back on track.