At last, an untroubled afternoon for Chelsea

Four goals, a clean sheet, harmony in the stands and blue skies over Stamford Bridge. With the sun on your face on Sunday lunchtime you could have mistaken Chelsea for a club at peace with itself.

It is seldom that simple in SW6 but in this comprehensive defeat of Brentford, Chelsea enjoyed one of their least-troubled afternoons of a difficult season.

Roman Abramovich, making his first visit to Stamford Bridge this month, saw his club dispatch their League One opponents in the -manner he would expect of European champions. Avram Grant was in the crowd too, and the pair shared a handshake, but on this evidence the Israeli, on permanent stand-by for a Chelsea crisis, will remain a social visitor.

Having withstood a spiky, spirited first-half display from their near-neighbours a second-half salvo of four goals in 26 minutes from Rafael Benitez's side settled the contest. Goals from the outstanding Juan Mata and Oscar ended Brentford's resistance, and two more from Frank Lampard and the returning John Terry left the home supporters praising heroes of happier days.

It was not always pretty. Gary Cahill and David Luiz were both guilty of dangerous challenges that received minimal punishment, the latter for a gratuitous body-check that left 19-year-old Jake Reeves with concussion but was punished only with a yellow card.It was effective though, and there was even time for club, manager and captain to unite against reports of division, with Terry and Benitez dismissing suggestions of a rift between them as "rubbish".

Terry's role in the team has become an issue as he has struggled to return from a knee injury suffered in mid-November and that has granted him only two starts since. Benitez left him out of the team that played in Prague last Thursday, citing the superior fitness and form of Gary Cahill and Branislav Ivanovic and saying Terry will have to fight for his place.

Terry said he was happy with his lot: "The manager knows me and I want to play. I have been out for two or three months [with a knee injury], but the other two [centre-backs] have been doing well. It's good to have competition." Benitez said: "We do not have any problem."

After Brentford came within six minutes of the shock of the round at Griffin Park a fortnight ago the Chelsea manager took no chances, selecting a full-strength side capable of coping with the physical challenge of Uwe Rossler's team.

Cahill joined Terry at centre-half, Victor Moses returned to the right side of midfield for the first time since returning from Nigeria's triumphant Africa Cup of Nations campaign, and David Luiz and Demba Ba returned having missed the game in Prague.

Brentford showed two changes from the side that almost produced the shock of the fourth round. Jake Bidwell and Tom Adeyemi returning, and Rossler again set his side up to harry Chelsea and hope to provide the splendidly named Marcello Trotta with chances on the break.

For much of the first half it worked. While Chelsea dominated possession they struggled to create clear chances against energetic opponents as committed in the tackle as their 6,000 supporters in the Shed End.

Chelsea gave as good as they got and Cahill was fortunate to escape without a card after a dangerous, studs-up lunge raked Jonathan Douglas's shin.

They also enjoyed good fortune when referee Neil Swarbrick blew for a foul moments before Trotta shot past Petr Cech late in the first half. Luiz had fouled Adam Forshaw, but Swarbrick's failure to play the advantage cost Brentford the lead.

For all the brawn on display the game turned on the brilliance of Mata, the slightest player on the field but also the best. While Chelsea fans fret over the future of Lampard and Terry, it is the Spaniard who is irreplaceable. He is the creative fulcrum of this team and its leading scorer, and while Oscar and Eden Hazard acclimatise to English football he has delivered consistently all season.

He scored one and made one here, and left the field with 15 minutes remaining to a standing ovation. His 17th goal of the season came on 55 minutes via route one, Mata -collecting Ba's knock-down and driving left-footed past Simon Moore from 20 yards. Oscar scored the second 13 minutes later with a touch of finesse, a back-heel from Ivanovic's cross eluding the goalkeeper and three Brentford defenders including Harlee Dean on the line.

Lampard and Terry then added polish to the scoreline, the former with a cushioned volley teed up by Mata that takes his club total to 199, and the latter with a far-post header from Oscar's cross.

Players and crowd exchanged applause as they left the field, but the sense that this season is the end of an era remains. For Benitez meanwhile there was only indifference. This was the first game since he arrived that featured no direct verbal abuse. For him, that counts as a very good day indeed.