André Villas-Boas sparked a blazing row with some of his senior Chelsea players on Sunday after calling the squad in on their day off to vent his anger over the 2-0 defeat at Everton. The manager tore into his players, who had pockmarked their display with sloppy errors, but he found that some of them gave back as good as they got. In the blow-up, they told him exactly what they thought of him and his tactics, to lay bare the tensions at the club.

Villas-Boas believes that he has the support of the owner, Roman Abramovich, who was also present at the training ground on Sunday. Abramovich's focus is no longer consumed by his $5bn (£3.2bn) litigation battle with Boris Berezovsky – the high court hearing ended on 19 January and Mrs Justice Gloster is in the throes of writing her judgment – and he has been a regular at Cobham since the Saturday before last which, inevitably, has heightened the pressure on Villas-Boas. Abramovich, though, does not want to sack the young Portuguese, having taken the decision on his own to appoint him as the successor to Carlo Ancelotti last summer, and he shared in the manager's frustrations with the players.

The defeat at Goodison Park, which exacerbated the club's Premier League slump and dropped them out of the Champions League places, was, by common consent, the team's worst performance of a season that has seen them fail to compete for the title. They lag 17 points behind the league leaders Manchester City.

A big part of Villas-Boas's brief is to rejuvenate the Chelsea squad, to assimilate talented young players while still competing for silverware. He has maintained that a club of Chelsea's stature cannot tolerate mere transition. But, inevitably, he has found himself unpopular with the older guard, whom he feels he must phase out.

He caused a stir with his man-management when he banished Nicolas Anelka and Alex to train with the reserves, after they had requested transfers in December; the popular pair departed in January for Shanghai Shenhua and Paris St-Germain respectively. Villas-Boas has also clashed with Frank Lampard and Didier Drogba while even the high-profile January signing, Gary Cahill, has been left bewildered at his treatment. He has played only once in his five weeks at the club.

Chelsea's hopes of a trophy have come to rest on the FA Cup and Champions League – the latter is the one that Abramovich covets above all others – and their next two fixtures are in those competitions. They play Birmingham City in the FA Cup fifth round at Stamford Bridge on Saturday before they travel to Napoli for the Champions League last-16 first-leg next Tuesday. The captain, John Terry, hopes to return from a knee injury to face Birmingham, while Drogba and Salomon Kalou are due back on Wednesday from the Africa Cup of Nations.

The pressure in each tie will be intense, with the resentment towards Villas-Boas in some quarters adding further spice. Villas-Boas's assistant, Roberto Di Matteo, is also under scrutiny, with Abramovich picking up on the feeling during his visits to the training ground that the former Italy international is unpopular with the players. Abramovich turned to Villas-Boas after dismissing Ancelotti at the end of last season following, coincidentally, a Premier League defeat at Everton, having been impressed at how the 34-year-old won the treble of league, cup and Europa League with Porto. He is desperate for Villas-Boas to succeed, not least as firing him would call into question the wisdom of investing such faith in a talent without an extensive track record.

It is never prudent, though, to second-guess Abramovich, who has sacked five managers during his eight-and-a-half-year stewardship of the club. He dismissed Luiz Felipe Scolari in February 2009 when the club's membership of the Premier League's top four was in jeopardy. Villas-Boas is acutely aware of the need to qualify for next season's Champions League.

The fallout from Everton in the Chelsea dressing room also featured a candid assessment from the goalkeeper Petr Cech. "When you lose a game 2-0 and you are Chelsea football club, playing for the Champions League and with big expectations, losing is not good enough and the performance was not good enough. That's why we lost.

"We took so many passes side to side and we never really opened them up. In the second half, we tried to play more direct but they were fighting well and kept organised, and 1-0 up so early became so much more difficult to break."