Mercedes started off the year dominating, claiming five one-two finishes in a row and finishing on the top spot until Verstappen took the win in Austria.
The Dutchman won again in the chaotic mixed weather race in Germany and nearly claimed a third victory in Hungary after qualifying on pole for the first time in his career, but narrowly lost out to Lewis Hamilton on a different strategy.
Red Bull initially struggled to get on top of the aero regulation changes from the previous season, but after bringing in updates around Austria they are now back competing at the front of the field.
Horner said after the Hungarian Grand Prix: “Thank god for Red Bull and Max Verstappen for Formula 1 at the moment, otherwise it would be a fairly boring show.
“I think it’s great to have races like today, even though we didn’t come out on top, it’s what fans want to see.
“I think the last four races, in reality, have been great races after the bore-fest of France.
“Hopefully with the tracks we have coming up, there is exciting races to come and if the grid does concertina and Max can race against Lewis and the Ferraris as well then it is bright for the future.”