#2 Drew McIntyre

This is perhaps the biggest dream match The Undertaker can have on the current roster now that he's faced AJ Styles. At Extreme Rules 2019 in their previously mentioned tag team match, The Undertaker would have a face-to-face confrontation with Drew McIntyre, teasing the possibility of a feud down the line.
Such face-offs aren't done without intention and had The Undertaker not retired, we do not doubt that WWE would have liked to book this match, likely with the intention of helping McIntyre in his run on the top.
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The "new" Undertaker would have made for a great WWE title opponent, but either way, it's a match that we're never going to get. Drew McIntyre revealed that he was supposed to face The Undertaker at WrestleMania 26 when he was just 24 years old, but admitted that he wasn't ready at the time:
“When I was 24 I was told by Vince McMahon, ‘you don’t listen to anybody but the Undertaker, he’s going to be your mentor and whenever you’ve got a question you go straight to him’. And the inevitable goal was to have a big match between him and I. Unfortunately I wasn’t ready at the time, things worked out the way they worked out, and I believe it led to, instead of myself and Undertaker, Shawn Michaels and Undertaker, the retirement match. It was obviously a phenomenal match and I could not have delivered on that level at the time.”
McIntyre is right in believing that he wasn't ready. 2020, however, would have been a whole different story.
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