Match ends, Barcelona 4, Roma 1.
Luis Suarez scored his first Champions League goal in more than a year as Barcelona beat Roma convincingly in the quarter-final first leg.
Barca benefitted from two own goals to take control of the tie.
First Daniele de Rossi slid into his own net in a bid to keep the ball away from Lionel Messi, and then Kostas Manolas bundled another in, with Gerard Pique tapping in Barcelona's third.
Edin Dzeko gave Roma hope - but Suarez then slammed home from 14 yards.
Barca are strong favourites to clinch their first semi-final spot since 2014-15, when they won the tournament, next Wednesday at the Stadio Olimpico.
Barcelona treble dreams still on course
Ernesto Valverde's Barcelona - nine points clear at the top of La Liga and in the Copa del Rey final - did not even need to play well to brush Roma aside - and they could have won by more.
Suarez had a goal rightly ruled out for offside and Ivan Rakitic hit the post before Roma captain De Rossi slid Andres Iniesta's cross into his own net from about 16 yards out.
Roma did have chances and could have had a penalty when Samuel Umtiti fouled Lorenzo Pellegrini right on the edge of the box near the end of the first half, but referee Danny Makkelie awarded a free-kick to Roma instead of a spot-kick.
Twenty seconds after the restart, they went close when unmarked Diego Perotti's header from Alessandro Florenzi went wide.
They trailed by two when Umtiti hit the post and Roma defender Manolas put the rebound in before the Barca man could do it himself.
Pique tapped in after Suarez's shot was parried. But Dzeko got what looked an important away goal when he converted Perotti's low cross.
The tie was all but ended when Suarez smashed home from Denis Suarez's cross for his first Champions League goal in 11 games - a statistical anomaly for a striker who has scored 22 goals in 26 La Liga games this season.
Lionel Messi had seven shots, three on target, but failed to score for the first time in eight games.
Barca get a helping hand again
For a team who score with ease themselves, Barcelona do not need any assistance to get on the scoresheet.
But they have now benefitted from more Champions League own goals than any other team in a single season.
Opposition players netted for Barcelona in three of the four group games that Barca managed to score in - Sebastian Coates and Jeremy Mathieu for Sporting Lisbon in different matches and Dimitris Nikolaou for Olympiakos.
De Rossi and Manolas' efforts against Barcelona, both of which were unlucky, mean that Lionel Messi is the only Barcelona player, with six, to net more times than own goals in the Champions League this season.
"It's not just luck that we get own goals in our favour," said Pique. "Things happen for a reason. If these goals go our way it's because we press high, we push up in attack - the ball is in the opposition area more than usual in other teams' matches."
'Messi's worst performance of the season' - view from the Nou Camp
Spanish football writer Andy West
This was a far better result than performance for Barcelona, who needed two own goals to establish a surely insurmountable advantage against a relatively weak Roma team.
The Spanish side lacked fluency and control in their attacking play throughout the game, and were looking at a potentially uncomfortable second leg before Suarez restored the three-goal margin near the end thanks to a poor piece of Roma defending.
Particularly notable was a rare off night from Messi, who was desperately lacking in rhythm as he made his first start in two and a half weeks and lost possession on seven occasions in the first half alone.
Messi improved after the break but still could not get on the scoresheet despite a couple of decent chances - one of which he uncharacteristically smashed miles over the bar after being well picked out by Jordi Alba. That summed up his night and this was probably his worst performance of the season.
Barca were also less than solid at the back, where Marc-Andre ter Stegen nearly gifted a goal to Roma with a terrible clearance and the usually reliable Umtiti was lucky not to concede after ponderously failing to clear a routine cross.
Tactically, the chief point of interest was the decision of Valverde to overlook flying winger Ousmane Dembele, who adds another dimension to his team's attacking play but can be a liability defensively. Whether Valverde can afford to be so cautious against Liverpool, Real Madrid or Bayern Munich in the semi-finals is highly debatable.
'Roma should have had a penalty'
Roma striker Dzeko felt he should have had an early penalty when he went down under pressure from Nelson Semedo - with referee Makkelie awarding a goal-kick.
"The penalty could have changed the game," he said. "The referee needs to have the courage to give a penalty against Barcelona, because we are also in the quarter-finals and all of the teams here have earned the right to play.
"I don't know whether it's a question of mentality; they are a better side than us and everyone is aware of this - 3-1 would have been a better result but when you make so many errors against a side this good you get punished."
Valverde said: "Football is a game of errors. You want to make your rivals commit them and to avoid them yourself. We all want our players to be perfect and never make errors but we all do. Even coaches.
"During the season there are all types of games. Ones where you merit more than you get and ones were you get more than you merit.
"We scored the goals we merited, they attacked us and got the goal they were looking for, which made our fourth very important."
- Barcelona have won 20 of their past 21 Champions League games at the Nou Camp [drawing the other], including each of their five games this season.
- Roma have conceded 11 goals in their three Champions League trips to Barcelona - more than against any other side on the road in the competition.
- Roma are just the third different side to breach Barcelona's defence at the Nou Camp in the past 10 Champions League games after Paris St-Germain and Olympiakos.
- Manolas' own goal was the 13th that Barcelona have benefited from in the Champions League; only Real Madrid (15) have benefited from more.
- Roma are just the fourth side in Champions League history to score two own goals in a single game and the first since Galatasaray in September 2015 against Astana.
- Iniesta made his 21st quarter-final appearance in the Champions League - a joint record with Ryan Giggs and Xavi.
- Only Roberto Carlos (16) and Ivan Helguera (15) have scored more goals than Pique (12) amongst defenders in the Champions League.
- Dzeko has had a hand in 58% of Roma's 12 goals in the Champions League this season [five goals, two assists].
- After failing to score with his first 30 shots in the Champions League this season, Suarez finally scored with his 31st effort.
Man of the match - Gerard Pique (Barcelona)
Barcelona can take another step towards winning La Liga when they host Leganes on Saturday. Third placed Roma are at home to Fiorentina on Saturday in Serie A.
- 1ter Stegen
- 2Nélson Semedo
- 20RobertoSubstituted forAndré Gomesat 83'minutes
- 5BusquetsSubstituted forPaulinhoat 66'minutes
- 8IniestaSubstituted forD Suárezat 85'minutes
- 6D Suárez
- 21André Gomes
- 25da Silva Peres
- 11KolarovBooked at 44mins
- 24FlorenziSubstituted forEl Shaarawyat 72'minutes
- 6StrootmanBooked at 86mins
- 16De RossiSubstituted forDefrelat 77'minutes
- 7PellegriniSubstituted forGonalonsat 60'minutes
- 5Nunes Jesus
- 30Santos da Silva
- 92El Shaarawy
- Danny Makkelie
- Shots on Target
Second Half ends, Barcelona 4, Roma 1.
Corner, Barcelona. Conceded by Edin Dzeko.
Foul by Denis Suárez (Barcelona).
Bruno Peres (Roma) wins a free kick in the defensive half.
Attempt missed. Aleksandar Kolarov (Roma) left footed shot from outside the box is just a bit too high from a direct free kick.
Foul by Denis Suárez (Barcelona).
Gregoire Defrel (Roma) wins a free kick in the attacking half.
Goal! Barcelona 4, Roma 1. Luis Suárez (Barcelona) left footed shot from the centre of the box to the bottom right corner.
Kevin Strootman (Roma) is shown the yellow card for a bad foul.
Lionel Messi (Barcelona) wins a free kick in the defensive half.
Foul by Kevin Strootman (Roma).
Substitution, Barcelona. Denis Suárez replaces Andrés Iniesta.
Foul by André Gomes (Barcelona).
Diego Perotti (Roma) wins a free kick on the left wing.
Substitution, Barcelona. André Gomes replaces Sergi Roberto.
Attempt missed. Lionel Messi (Barcelona) left footed shot from the centre of the box is too high. Assisted by Jordi Alba.
Foul by Gerard Piqué (Barcelona).
Gregoire Defrel (Roma) wins a free kick on the left wing.
Goal! Barcelona 3, Roma 1. Edin Dzeko (Roma) left footed shot from the centre of the box to the bottom left corner. Assisted by Diego Perotti.