"He (Carvalho) has caught him (Keane) and what Robbie's done is try to stay on his feet, and that is what happens," Redknapp told Sky Sports after the 3-0 defeat at Stamford Bridge.
"If he had gone done when he had lost his balance it is a nailed-on penalty but he tried to stay up and it is a difficult one.
"If he felt he had dived then why didn't he give him a card, it is either a penalty or a card.
"We had him (Webb) at Old Trafford last season and he cost us the game with a diabolical penalty decision that he apologised for after.
"For the first 30 minutes we were the better team but I thought the key points went against us and we didn't defend well enough for the second goal."
"But we are not that far away from being a very good side and I think we will get there eventually."