Antonio Conte can do no wrong. The Chelsea manager watched his team ease into the fifth round of the FA Cup at the expense of Brentford, who did not turn up until the second half, and the icing on the cake was provided by Branislav Ivanovic – a player he had dropped from the starting line-up.

Conte introduced the Chelsea stalwart, whose future is uncertain, as a 64th-minute substitute and, with his first meaningful involvement, he scored his first goal of the season to make it 3-0. Ivanovic gave the ball to Pedro and rumbled forward in support before getting it back and squeezing a low finish underneath the goalkeeper Daniel Bentley.

There was more. Ivanovic got himself into the area towards the end and, when he was taken out by Yoann Barbet, the referee, Michael Oliver, pointed to the penalty spot. Michy Batshuayi scored to round off Chelsea’s 17th win in their past 19 matches in all competitions. For the Premier League leaders, the double remains on.

Conte made nine changes to the lineup who had beaten Hull City in the league last Sunday – retaining only Pedro and César Azpilicueta – but it did not matter. Chelsea had cohesion and punch where it mattered, with Pedro outstanding and Willian and Ruben Loftus-Cheek not too far behind. Pedro scored the second goal – his eighth of the season – and had a hand in the first and third.

Brentford were off the pace in the first half and Dean Smith suggested his players had “subconsciously dropped a bit deep” after Pedro’s goal in the 21st minute. They were better at the beginning of the second half and Chelsea were indebted to Asmir Begovic for denying Lasse Vibe and Nico Yennaris.

There is the possibly that this might have been the last game for Ivanovic and Begovic in Chelsea colours, with Zenit St Petersburg among the clubs keen on taking the former before Tuesday’s transfer deadline and Bournemouth pushing for the latter.

Conte made it clear he was open to either player leaving, although he would first demand a replacement for Begovic. “Ivan is not playing a lot and that is difficult for him,” Conte said. “In this situation, the player must make the best decision for him and his family. Has Ivanovic asked to leave? I prefer to keep those conversations private. Begovic is in the same situation as Ivan.”

Chelsea’s opening goal came early and it was a beautifully executed free-kick from Willian, which he got to dip sharply after it had cleared the defensive wall. Smith described the award as “harsh” but Vibe had checked Pedro after a Chelsea short corner routine. It was Willian’s seventh goal of the season.

It was men against boys in the first half and the only surprise was Chelsea did not rack up more goals. Pedro scored with a touch and low finish following Batshuayi’s ball forward and the home team had many more chances, with the marauding Loftus-Cheek showing his power and a deft touch, too. He had three sightings of goal before the interval and from two of them he forced Bentley into smart saves.

Bentley managed to deny Batshuayi at close quarters following a goalmouth scramble on 27 minutes, scruffily halting the ball on his own line and later touched Cesc Fàbregas’s low shot from distance past the post. John Terry and Batshuayi had chances and Brentford could not wait for the half-time whistle.

The Championship club brought 6,000 fans and they found their voices when their team began the second half with a little more hustle. Smith had asked his players during the break whether they wanted to let Chelsea continue to have it all their own way and the response was good.

They got into their opponents’ faces and they had openings – two presentable ones; the first on 48 minutes. It was teed up by Ryan Woods for Vibe, who had got the better of Terry but Begovic left his line to claw the ball from him.

The second came on 63 minutes and it followed a piece of skill inside the penalty area from Yennaris of which Dennis Bergkamp would have been proud. Yennaris pirouetted away from Terry and Azpilicueta to open up the opportunity but again Begovic was out quickly to block. Smith sent on Scott Hogan, the West Ham United target, for whom this might have been a farewell appearance and the travelling support roared their encouragement, but Chelsea were on another level. Loftus-Cheek hit the crossbar after fine work from Willian on 58 minutes and went close following another surge, before Ivanovic made his push for the headlines.