The five keys to Barcelona's embarrassing night in Rome

Barcelona were knocked out of the Champions League in the quarterfinals once again. Their loss to Roma saw them eliminated in the last eight for the third time in as many years and the fourth time in the last five years -- the only exception being when they won the tournament in 2015. 

Here are some of the keys which help understand Barça's unexpected European exit. 

1 - An overused, ageing team 

Ernesto Valverde has repeated the same lineup in recent games, using the same base and demanding his regulars play every three days. Hardly any players have been afforded rests, with the majority of the spine either older than 30 or nearing 30. Barça have always struggled to rejuvenate themselves, prisoners of their success of the past, and this season has been no different. 

2 - No confidence in the bench of the signings 

Only one player signed last summer started in Rome: Nelson Semedo. Philippe Coutinho can't play in the Champions League, Paulinho's role has become more limited and Ousmane Dembele's still finding himself at the club. Barça lacked depth and flexibility to change the direction of the match. There's no Plan B and when there is it is not enough, urgent and improvised. The lack quality substitutes and the signings have not helped the team's demands. 

3 - What's after Messi? 

Messidependencia is a blessing when the Argentine is in form, but a curse when he has an off day. As ocurred against Juventus last season, Messi didn't get into the game against Roma and Barça paid for it. Their attacking play depends on the No. 10 and there are no solutions without him. The late alternatives in Rome (Alcacer and Dembele) were too late and rushed -- they had no time to affect the match.

4 - Ernesto Valverde's planning 

With a more conservative plan, Valverde transmitted to his players a message of fear. It was about protecting what they had. With a goal, Barça would have been almost in the semifinals, but Valverde took a step back. Barça aren't a team designed to defend. They suffer without the ball and aren't the same team without possession. If they're not defending with the ball, they struggle. And how. Valverde was then unable to correct it. 

5 - Aiming too big 

Aiming to win everything has damaged Barcelona. The dream of winning the treble has ended up being an unrealistic target. Barça never had the squad for it. And it showed at the worst moment possible. It showed that they had put too much in during the winter moneths, in January and February, for example, when they fought hard to reach the Copa del Rey final. And when they fought hard to keep their unbeaten run going in La Liga. The priority should have been to get to April fresh, when the Champions League ticks into the moment of truth. But Barça arrived mentally exhausted and physically struggling.