Guus Hiddink accused Watford of provoking Diego Costa ahead of an incident with Juan Carlos Paredes that sparked a melee during Chelsea's 0-0 draw at Watford.
A run-in during first-half stoppage-time between Paredes and Costa at Vicarage Road saw the players go to ground easily under minimal contact from one another in quick succession, with referee Mike Dean prompted to show the duo yellow cards.
Troy Deeney plans to discuss the issue with his Watford team-mate, but Chelsea boss Hiddink accused the opposition of trying to rile his Spain striker.
"It was very close to us so we saw what happened," Hiddink told BT Sport.
"Paredes gave him a push in the back and after that the two of them were stumbling and he [Paredes] brought his hands to his face. Diego was not near his face, they just stumbled a bit.
"So they tried to provoke Diego a bit, but I definitely have to defend him on what I see which is the reality of what we saw just in front of our eyes.
"When they are provoked I protect my players. He was very calm at half-time and we were focused on getting our goal, and he was too."
Hiddink believes Chelsea are improving with every performance and felt they would have won the Premier League clash had it not been for Heurelho Gomes - who he coached at PSV between 2004 and 2006 - producing saves to deny Branislav Ivanovic and Costa in the closing stages.
"We are playing better and better every week. I like to see. How the team is playing, especially in the last 20-25 minutes when we pushed," he said.
"Once more I think my old goalie from a previous spell, Gomes, got a big reward, otherwise I think we would have won easily."
Despite scoring his first goal for Chelsea this season in Sunday's 5-1 win over MK Dons in the FA Cup, Eden Hazard was a substitute for the trip to Vicarage Road.
Hiddink insisted the decision was solely down to managing his recovery from a groin strain.
"We know what period of his recovery he is in. He is coming back to a level we like to see him at. He played last week and has been out for too long," he added.