Pandey's 64 was Kallis' 72 were the cornerstones of KKR's 163-run total, which helped them clinch a 41-run win over the fancied Mumbai.
The duo's 131-run stand was the highlight of the IPL's opening match.
"When I went out there to bat, I remembered the old times when I batted with him and I realised nothing had changed. It was exactly the same batting with Jacques again and I could feel that same comfort level. We had a lot of partnerships together with RCB and we know each other's games well. We kept talking throughout our time together in the middle," Pandey said.
Reflecting on his IPL career so far, Pandey conceded that he lost his way after becoming the first Indian to score a hundred in the tournament in 2009.
"I think I was a bit off the radar. I wasn't consistent. I was doing well at the domestic level, in first-class cricket, but I couldn't bring that in the IPL.