As you probably know, both Keller and Spencer spent quite a few years in the EPL and met each other on the pitch numerous times. Keller was a goalkeeper at Millwall and Spencer was a forward at Chelsea in the 1990s. The two London-based clubs shared quite the rivalry in those days, and Spencer and Keller played a significant role in one particularly memorable moment.
With the game in penalties, Keller stopped a shot from Spencer to clinch the victory. Almost immediately, Millwall fans stormed the pitch, kicking off what can only be described as a riot. Here's how Spencer remembered it, according to the Seattle Times:
"Yeah, we were playing Chelsea and John was the fifth shooter. We had scored the fifth, then I saved John's penalty and we went through to the third round of the FA Cup, knocking out Chelsea. I like to remind him a lot when I see him. But like I've said, John's a great guy. He's a good personality for this rivalry and I'm just looking forward to Saturday and letting the play dictate what happens."
We even have video: