Richard Keogh admits Derby will have to be wary of his old club Carlisle United having a "free hit" at causing a cup shock tonight.

The former Blues defender says Keith Curle's side will have nothing to lose when they face the Rams in the EFL Cup second round (iPro Stadium, 7.45pm).

And Keogh, a big fans' favourite during his time with United, says the Championship outfit cannot afford to take his former employers for granted.

The Ireland international told the News & Star : "Carlisle have had a good start to the season, after a solid season last year.

"It's going to be up to us to make sure we impose ourselves on the tie.

"It's a free hit for Carlisle in some ways, with nothing to lose, and we've got to make sure we're ready for that.

"Hopefully our quality will shine through in the end. But it's going to be hard work and a tough game."

It will be a second opportunity for Keogh to face the Cumbrians in recent years, the 30-year-old having also featured in Derby's 2-0 win at Brunton Park in 2014.

The defender spoke about his debt of gratitude to the club where he made 95 appearances from 2007-10 before joining Coventry.

Keogh transformed his career at Carlisle and became a cult figure among fans, some of whom saluted the defender with a banner saying 'In Keogh We Trust'.

He said: "It was an important move for me at the time. I needed to get away and concentrate on football, reassess everything - and I couldn't have chosen a better club.

"I had two great seasons there and it definitely helped improve me as a player and helped my career.

"I'll always look back on my time at Carlisle as a really positive one. It was a real family club and a great time for me.

"The fans were incredible with me and we had a good relationship. I think we helped get the best out of each other. They gave me a lot of energy and I like to think I repaid them with my performances.

"It was great for me to see the fans in the game at Brunton Park a couple of years ago - and it was nice of the lads to bring the flag back out.

"I'm sure a few will travel down [tonight] and it will be nice to see them."

United's side could include Keogh's former Blues team-mate Luke Joyce, while the defender says he has faced winger Nicky Adams several times.

He says Derby, managed by former Carlisle chief Nigel Pearson, will be taking the cup seriously.

Keogh added: "For us it's about building momentum and the more games you can win, the better.

"The manager's mentality is to try and win every game, and as a group it's what we try to do. There's no better feeling than when you win games.

"We know the strengths of the Carlisle team and won't take it for granted."