Chelsea manager Liam Rosenior has complained about Arsenal’s pre-match “mind games” after Arsenal’s players encroached onto their half of the pitch during the warm-up.

Rosenior’s Chelsea side crashed out of the Carabao cup “with a whimper” on Tuesday night, succumbing to a late Arsenal goal from former-Blue Kai Havertz.

Conventionally, each team is allocated one half of the pitch to prepare for the game. But Rosenior accused Arsenal players and/or staff of violating this “etiquette.”

“When you warm up, we have our half and the other team have their half. I’ve never asked my team or coaches to encroach on the other team’s territory. I thought they were affecting our warm-up.”

SkySports cameras captured the coach’s foul-mouthed exclamations aimed at Arsenal team members, telling them in no uncertain terms to stay in their half. The precise details of these words are not fit for publication.

His complaints have sparked a debate about the place of “mind games” in sport, with some players and teams aiming to gain a psychological advantage over their opposition.

From Sunday League to the Premier League, from swampy park pitches to smooth stadium surfaces, passionate sportspeople will do almost anything to get an edge on their opponent.

This incident is a glimpse of the sporting gamesmanship which happens every weekend. The only difference is it’s not normally caught on camera and broadcast to the world.

How far is too far?

The spirit of sportsmanship is a delicate thing, especially when it comes to London derbies. Especially when they’re playing for a place in a Wembley final.

A recent poll showed that 56% of respondents thought the incident was a “non-issue,” while 44% believed Arsenal should have stayed in their half.

What do you reckon? Unacceptable gamesmanship? Or just part of the game?

Rosenior went on to say:

“I don’t have an issue with anyone at Arsenal. Mikel [Arteta] is someone I’ve got so much respect for. It was just in that moment, I don’t think that respect was shown to my team.”