Join the debate at #bbcfootballpublished at 20:45 Greenwich Mean Time 18 March 2015
Gary Lineker
BBC Sport
"A measure of Messi's greatness is that he makes world class players like Aguero and Suarez look distinctly ordinary by comparison."
City knocked out after 3-1 aggregate defeat
Aguero pen saved by Barca keeper Ter Stegen
Mascherano had brought down Aguero on 77 mins
Rakitic lobs Hart after sublime Messi pass
Tom Rostance
Gary Lineker
BBC Sport
"A measure of Messi's greatness is that he makes world class players like Aguero and Suarez look distinctly ordinary by comparison."
Would a coach have put Diego Maradona and Lionel Messi in the same team though? Who would you leave out?
Former Liverpool striker Stan Collymore:, external
"Maradona.
"Did it with no ref protection, took Serie A equivalent of Newcastle to league title. Won World Cup almost alone."
Two goals for City and we'll go to extra time - providing they don't concede of course.
What odds on that happening?
Lionel Messi had 56 touches in the first half, more than anyone else.
He had three shots, nobody else had more.
He had an assist and more passes (38) than anyone else.
The first goals have been chalked up in our trio of domestic matches this evening.
Nottingham Forest have two of them in their match at home to Rotherham, Dexter Blackstock with a precise lob two minutes before the interval before Michail Antonio's wonderful run and 25-yard shot made it 2-0 just moments later.
In the night's other Championship game it's 0-0 between Fulham and Leeds in an 20:00 GMT kick-off at Craven Cottage, while in League Two Southend are 1-0 up on leaders Burton thanks to Barry Corr's goal in first-half injury time. Corr had earlier seen a penalty saved by Burton goalkeeper Jon McLaughlin.
Chris Waddle
BBC Radio 5 live
"We talk about the English champions. It just shows the gulf between the teams. People said to me at the start of the season that Barcelona were not the force they were. Think again. It could have been five already."
Of course, the beauty of the Ronaldo or Messi argument is that on Sunday we will see them play each other. Join us for El Clasico on Sunday night.
Gary, you've just opened the most popular argument in football. Where's Team Ronaldo?
Gary Lineker
BBC Sport
"Messi is indisputably the greatest player ever to don a pair of football boots. Don't even attempt to argue the point."
Half-time in Dortmund too, where it looks good for Juventus.
The champions of England are being taught a lesson. And it's a beautiful lesson to watch.
Barca hit the post again! Luis Suarez beats a brittle offside trap to run in on Joe Hart, who has my sympathies at the moment. Suarez lifts it over him first time, is it going in? Is it going in? It is you know...no! Off the post and wide.
Robbie Savage
BBC Radio 5 live
"No exaggeration, Barcelona should be four up against a Man City side committing fouls and which has been in Barcelona's penalty area once. Very poor. You've got to work hard and some of the City players are jogging."
Sergio Aguero has a shot well blocked from 25 yards, if they can get one back there's some hope. But Barca look like scoring three or four. They are in the mood.
Tim Arstall: City's full backs just aren't good enough here, not enough cover on the wings from Sagna or Kolarov
Colin Todd: Terrible positional play from Sagna. He is not good enough for this level
Samirhussen: The last thing City need : a red card! calm down Nasri.
Barca are trying to walk it in! And they nearly do. Need I say that Lionel Messi is the architect? Wriggling out of two tackles and then scooping a pass that blindsides the City backline. Neymar is in, he squares it when he could have shot and it is deflected wide.
Showboat stuff! From the corner Barca catch City asleep and Luis Suarez should score, planting a free header wide.
Only David Silva and Bacary Sagna have had more touches for City than Samir Nasri so far. He's having some influence.
But not as much as Lionel Messi, who nutmegs James Milner to leave the watching Pep Guardiola with his head in his hands. Messi is mesmeric at the moment.
Andy West
Spanish football writer in at the Nou Camp
"Manchester City look utterly gone after that opener. Their body language says they know they are beaten. That hack was a sign of their frustration. At this rate, the only way they'll avoid a heavy beating is if Barca ease up to save energy for Sunday's Clasico."
Robbie Savage
BBC Radio 5 live
"That is ridiculous from Nasri. He has just booted Neymar. Instead of booting people, try and have an influence on the game going forward. That's just pathetic."