The full-back is set to line-up for his third-successive start for us in the Premier League having won two out of two so far against Hull and Everton.
Jose Mourinho’s squad have made an impressive start to the campaign with 10 wins and three draws from their 13 matches so far.
Neverthless, Ben says we travel to West London with confidence having lost just one of six away games in the Premier League.
“It’s a massive game for us and one we have to go in to with no fear,” said the Welsh international.
“If we do that then hopefully we’ll pick up a positive result.
“We’re focused 100 per cent and we have to continue to show that confidence away from home.”
Chelsea’s top-scorer Diego Costa - 11 goals in the Premier League - is suspended but Ben added: “I’m pretty sure they’ll have someone decent coming in to replace Costa but we have to be tight as a unit and if we do that, there’s a good chance we can pick something up.
“These are the games you want to be involved in. I’m sure it will be a great occasion.”