The GRT Yamaha Official WorldSSP Team came through a testing Friday during Round 4 of the 2018 FIM Supersport World Championship at a hot and sunny TT Circuit Assen. Federico Caricasulo, unusually, was slow out of the blocks in FP1 before working hard throughout the day to improve and set a 1:39.114 in FP2 to finish sixth on the combined timesheets. His teammate and WorldSSP Championship leader, Lucas Mahias, also struggled to gel with his Yamaha R6 his usual fashion but was just a further 0.141s back from Caricasulo in seventh after setting a 1:39.255, with both riders making it through automatically to Saturday's SP2.