Shackell signed for Derby from Burnley this summer, in a transfer that the Derby Telegraph valued at £3 million.
And the 32-year-old has already impressed his new teammates, with his centre-back partner, Keogh, raving about his ability.
“I’ve really enjoyed playing alongside Jason; he’s a good player and he’s been a good signing for the football club," Keogh said.
“Shacks is great to play alongside and I think we suit each other quite well; we have a good partnership and understanding.
“It’s rare that something hits off so quickly but we’ve had that and I think it will only get better.
“He’s helped me and I would like to think I’ve helped him as well - the combination is good and long may it continue.”
The strength of Keogh and Shackell's partnership has formed the basis of Derby's success so far this campaign.
No team have conceded fewer goals than the Rams, who have only let the ball hit the back of their net seven times throughout their first 10 matches.
Keogh and Shackell are under pressure to keep their high standards up, as they have the likes of Alex Pearce and Jake Buxton waiting for an opportunity, should their form dip.
Despite their excellent defensive record, Derby are currently in seventh place in the Championship table, and they need to start finding more of a cutting edge to their play - having netted only 12 goals themselves.