Steve Bruce's side are gearing up to face the Rams at the iPro Stadium on a Saturday in a key first leg which will help decide who squares off with Brighton and Hove Albion or Sheffield Wednesday at Wembley.
With Derby hosting the opener, Horton, who managed City from 1984 until 1988, believes that it gives his former side a slight edge in the tie.
“Saturday was the first time I’ve seen Hull live this season and I think that was the best team that Steve Bruce could put out,” said Horton to the club's official website.
“It’s away for the first leg at Derby and then back to the KC for the second which is ideal so I think Hull have got a great chance. "
Another possible advantage for Hull is the fact that so many of Bruce's side have a taste for the Premier League, having been relegated from the top flight last season.
That being said, Derby may have something of a psychological edge after beating Hull twice already this season, by an aggregate score of 6-0, and Darren Wassall will be hoping his troops can replicate the 4-0 win last month.