Yeah, Maradona was a big deal already by then before the 1986 World Cup. I don’t know if he was Messi-level famous, but he was definitely a big star.
Wood was a very highly-touted prospect when he finally came up to the Cubs in '98, so it’s not like he came out of nowhere, and that 20-strikeout game was only his fifth major-league start. But, he did have to deal with a lot of injuries, and eventually wound up as a reliever. He did have stretches in which he played well – in 2003, he led the NL in strikeouts, won 14 games, was an All-Star, and had a bWAR score of 6.1 – but his career peak did happen on that one day in '98.
Yes, he was Mess-level famous already before the 1986 WC and unlike Messi rather unrivaled as the best footballer in the world at that time.
The first World Cup I was old enough to follow was the 1982 one in Spain.
Maradona was already very famous then, so much so that his being sent off in the second round was a big deal.