Chelsea duo Diego Costa and Oscar have been involved in an angry training ground confrontation.
The attacking pair had to be restrained after squaring up to each following a sequence of two hefty tackles during an intense training session on Thursday afternoon (UKT).
Oscar is understood to have rattled Costa with a hefty tackle before the Spain international responded with hard-hitting tackle of his own.
The second clash is understood to have sparked the heated confrontation between the pair, who had to be pulled apart.
The pair were separated before any punches were thrown.
The clash is said to have de-escalated quickly with the pair said to have resolved their differences with each other at the end of the training session.
Blues interim boss Guus Hiddink is said to be relaxed about the incident at the club's Cobham HQ but will be quizzed about the encounter at his scheduled pre-match match media conference on Friday.
Regardless, the incident will come as unwanted headache for the club ahead of the FA Cup tie against Scunthorpe this weekend and continues a miserable season.
TIMELINE OF CHELSEA'S DRAMATIC SEASON
AUG 8, 2015 - Jose Mourinho clashed with club doctor Eva Carneiro and physio Jon Fearn after taking exception to the pair going on to the pitch to treat Eden Hazard during Chelsea's 2-2 draw at home against Swansea. The now sacked manager then publicly criticised the medical staff after the match.
AUG 16, 2015 - Chelsea were handed a 3-0 defeat by apparent title rivals Manchester City which was brushed aside as a 'completely fake' result.
AUG 29, 2015 - Chelsea outplayd by Crystal Palace in a 2-1 home defeat. It was Mourinho's 100th game in charge at Stamford Bridge and only the second time his side had been beaten there. He threatened star players with the axe in the immediate aftermath.
SEP 12, 2015 - Mourinho walked out of post-match interview with BT Sports after his side were comfortably beaten 3-1 by Everton at Goodison Park.
SEP 19, 2015 - Diego Costa retrspectively banned for three games after clashing with Arsenal defender Laurent Koscielny. Chelsea won 2-0, though.
OCT 3, 2015 - Mourinho fined after a seven-minute rant on TV in he which Mourinho criticised referee Robert Madley's performance in their 3-1 defeat by Southampton. FA fined Mourinho £50,000 and handed him a suspended stadium ban.
OCT 21, 2015 - Film emerged of the Chelsea manager appearing to shove 14-year-old Otto Nahmmacher who was taking a video of him. Mourinho then threatens media blackout after the incident was reported.
OCT 24, 2015 - Mourinho sent off at half-time after Nemanja Matic was sent off in first half of 2-1 defeat by West Ham. Assistant first-team coach Silvino Louro also dismissed for haranguing the fourth official. Five other Chelsea players booked in the match. No Chelsea representative faced the media.
OCT 27, 2015 - Eden Hazard missed critical penalty in Capital One Cup shoot-out defeat at Stoke. Diego Costa limped off during the first half before Loic Remy scored 90th-minute equaliser to force extra time.
OCT 31, 2015 - Jurgen Klopp and Liverpool condemn Chelsea to yet another home defeat with a brace from Philippe Coutinho and a third from substitute Christian Benteke cancelling out Ramires' fourth-minute opener.
NOV 2, 2015 -Mourinho gets one-match stadium suspension with immediate effect and fined £40,000 after admitting an FA charge of misconduct over his behaviour at West Ham.
NOV 6, 2015 - The FA releases its written reasons for Mourinho's ban, saying he called referee Jon Moss 'f****** weak'.
NOV 7, 2015 - Mourinho absent as Chelsea lost to Stoke, their seventh Premier League defeat of the season, courtesy of a Marko Arnautovic volley.
NOV 21, 2015 - Mourinho claims he'd have to be 'Tom Cruise' to steer Chelsea to the title after Chelsea scrap past lowly Norwich with a Diego Costa winner
NOV 23, 2015 - It is announced that Chelsea made a loss of £23.1million in their Premier League-winning season.
NOV 24, 2015 - Costa and Mourinho have a shouting match at half-time to put a bit of a dampender on Chelsea's 4-0 Champions League win against Maccabi Tel Aviv.
NOV 29, 2015 - Costa dropped to the bench for the 0-0 draw at Tottenham and throws his bib in Mourinho's direction when it becomes apparent he would not feature.
DEC 5, 2015 - Blues fall again at home, this time to Bournemouth after Glenn Murray netted the 82nd-minute winner. Mourinho concedes his side should focus on making the top six.
DEC 14, 2015 - Chelsea beaten 2-1 at Leicester, putting the Foxes back top of the Premier League and leaving Mourinho's men one point above the relegation zone after nine defeats from 16 matches - Chelsea's worst start to a season since 1978. Mourinho says after the game that his work was 'betrayed' by his players.
DEC 17, 2015 - Mourinho sacked with Steve Holland and Eddie Newton taking care of the team against Sunderland
DEC 19, 2015 - Guss Hiddink appointed interim manager for a second time until the end of the season.
JAN 6, 2016 - Dr Carneiro appeared at an employment tribunal hearing for her constructive dismissal case. She is suing Chelsea. A separate but connected claim against Mourinho for alleged discrimination is being made. - Daily Mail