Red Bull team boss Christian Horner admitted to feeling thwarted by Ferrari's current underperformance which only highlights the unfair wins collected by the Scuderia last year, to the detriment of the Milton Keynes squad.
Ferrari enjoyed a significant boost of performance over the summer of 2019, which culminated with wins in Belgium, Italy and Singapore.
But several technical directive introduced by the FIA amid suspicions of cheating by the Italian outfit reined in the power of Ferrari's engine in the latter part of the season, an action by the governing body that was followed by a confidential agreement between the latter and the House of Maranello that capped even further the potential of the Scuderia's controversial unit for this season.
Horner says Ferrari's dismal performance this year has left Red Bull with "quite a sour taste", suggesting that his team was deprived in 2019 of several race wins - and additional prize money - that were pocketed instead by the Scuderia.
"The whole thing has left quite a sour taste," Horner explained in Spa last weekend.
"I mean obviously you can draw your own conclusions from Ferrari's current performance but, yeah, there are races that we should have won last year arguably if they had run with an engine that seems to be quite different to what performance that they had last year."
Mercedes boss Toto Wolff said in Spa that Ferrari's current woes were the result of ill-inspired decisions made by "certain members" on the Italian team. Horner echoed his rival's view.
"It's obviously very tough for them, but I think their focus has obviously been in the wrong areas in previous years, which is why they obviously seem to be struggling a little with whatever was in that agreement," said the Red Bull chief.
"I think you've got Mercedes as a clear leader, then I think Honda and Renault are reasonably close depending on circuits and conditions. And then you've got Ferrari obviously at the back of the queue."