Keegan was England's star man going into the tournament in Spain 35 years ago, but injuries to him and Trevor Brooking scuppered their dreams of glory.
"They might not have the numbers, but when they put 16 or 17 together, they've got a right good side".
"They're suffering the consequences of 25 years, 30 years, 40 years (of underachievement)".
"I did think we had a chance in 1982 until me and Trevor Brooking got injured", he recalled.
Captain Harry Kane scored in injury time early Friday (Thailand time) to give England a 1-0 win over Slovenia and a ticket to Russian Federation for World Cup 2018.
"They're young players that we have to try and get behind".
England, Northern Ireland, the Republic of Ireland, Scotland and Wales are all in World Cup qualifying action over the next four nights with all those countries still harbouring hopes of reaching the finals in Russian Federation next summer.
Stuart Pearce believes Southgate should appoint a permanent captain sooner rather than later and says Kane is a strong contender.
"We keep talking about world class players and until you are able to really perform and prove yourself on that stage then you can't consider yourself in that company, but, our lads now have the chance to play on that stage again".
"Congratulations to England", he said. "My desire and ideal way of playing and what we need to do over the next year are maybe two different things".
With qualification wrapped up with a game to spare, England plays their final game of Group F with a trip to Lithuania on Sunday. "But we do have goalscorers".
"But I think my players deserve congratulations as well and I think we played a decent game and they can be proud".