Estonia midfielder Konstantin Vassiljev has conceded that Slovenia are now favourites to finish third in Group E after beating the Baltic side on Tuesday.
Robert Beric's goal on 63 minutes in Maribor means that the Slovenians are two points clear of Estonia with two games remaining.
However, Vassiljev has bemoaned the defensive error that settled a tight game in the home side's favour.
He is quoted by UEFA.com as saying: "The match was very important for both teams and we both wanted a good result.
"Maybe it wasn't the prettiest of games for the fans. But that's the way it was supposed to be. I'm sorry that an error in defence cost us the game.
"However, I have to congratulate Slovenia. They are now favourites to finish third."
Estonia travel to Wembley to face England next month.