The Italian could have no complaints when referee Andy D'Urso brandished the red card for stamping on Blues midfielder Jody Morris in the 69th minute.
It was a wild tackle by Morris, who should clearly have been cautioned for his part in the trouble before his subsequent yellow card for a lunge on Joe Cole, but a repentant Di Canio admitted to Sky Sports after the game: "It wasn't nasty, but it was stupid."
It is the first time Di Canio has been sent off in his turbulent Hammers career, and he added: "I want to say sorry to my team-mates and our supporters. Sometimes it's important to accept your mistakes and recognise them."
Di Canio and fellow striker Fredi Kanoute, who was substituted late in the second half, hardly troubled the Chelsea defence and it was not until Jermain Defoe stepped off the subs' bench in the 80th minute, to claim a clinically-taken consolation goal, that the visitors posed a serious threat in attack.
But Di Canio denied that persistent talk of a possible move to Manchester United was playing on his mind at The Bridge. He says: "I am a West Ham player and by reacting the way I did to Morris showed that I cared about the fact we were losing 3-0 at the time. I wasn't thinking about any other club.
"I just want to do my best, but today wasn't my best."