The penultimate episode of BBC One's Line Of Duty trumped the return of ITV's Grantchester by more than two million viewers in Sunday night's ratings.
The Thandie Newton-lead police drama averaged an audience of 6.6 million, while James Norton's return attracted an average of 4.4 million.
The two shows went head to head in the 9pm slot and even at its peak of 4.7 million viewers Grantchester still had a two million shortfall in audience against its rival.
Line Of Duty has seen its weekly audience grow steadily since the show moved to BBC One in March. Previous series have aired on BBC Two.
Sunday night's other new addition, The Durrells, returned with an audience of 5.5 million viewers, peaking at 5.9 million.
The ITV drama is based on British naturalist Gerard Durrell's autobiographical books such as My Family And Other Animals, which document his childhood growing up on the Greek island of Corfu.
Keeley Hawes returns as Louisa, a widowed mother who moves her family to the island in the 1930s, for the second series.
The figures for ITV include viewers of the ITV+1 and ITV HD channels.
The drama went head to head with the final episode of Top Gear in the 8pm time slot.
BBC Two's motoring programme peaked with an audience of 2.1 million and enjoyed an average of 1.9 million viewers.
Viewers praised former Friends star Matt LeBlanc with "saving" the show as it came to a high-octane end with an episode that featured boat racing and nude ramblers.
LeBlanc returned to front the revamped series with Chris Harris and Rory Reid as co-hosts, following Chris Evans' departure last year.
Other weekend viewing highlights included 9.2 million people tuning in to watch the second episode of Britain's Got Talent on Saturday night.