ByKolles head of operations Boris Bermes made the claim after its ENSO CLM P1/01 driven by Tom Dillmann, Oliver Webb and Bruno Spengler outpaced privateer rival Rebellion during the wet conditions over the opening hours of the Spa 6 Hours on Saturday.
The car was able to maintain third position behind the two Toyota TS050 Hybrids until just before the halfway mark of the race.
The step-up in performance for a team that was returning to the WEC for the first time since last year's Le Mans 24 Hours followed a development programme focussed on the car's aerodynamics and reliability.
#4 ByKolles Racing Team Enso CLM P1/01 - Gibson: Tom Dillmann, Bruno Spengler, Oliver Webb
JEP / Motorsport Images
The updates to the ENSO CLM, which first raced back in 2014, include revised front-end aerodynamics and a new rear deck designed to reduce drag without sacrificing downforce.
It as running in a compromised low-downforce Le Mans spec at the weekend, whereas the Rebellion R-13 that struggled in the rain was in high-downforce trim.
Bermes admitted to disappointment that the ByKolles entry was unable to continue its strong form over the second half of the race. The car lost time late in the third hour when it needed attention to one of the FIA sensors that LMP1 cars run.
An electrical problem that resulted in a fuel pick-up problem subsequently forced the team to cut short its stints.
The car was running fifth overall in the final hour when a broken exhaust lambda sensor brought Spengler into the pits for repairs.
WEC debutant Spengler returned to the track for five laps at the end of the race, allowing the team to register a finish in 27th position.
The best result for the ENSO CLM, which was powered by AER and then Nissan engines before the switch to its current Gibson powerplant, is fourth place at Spa in May 2018.