The Aviva Premiership clash between Leicester Tigers and Northampton Saints, which finished in a thrilling 19-19 draw, attracted a peak audience of 228,000 and an average of 179,000 for the match, according to BARB (Broadcasters' Audience Research Board).
It was closely followed by the 175,000 average for Harlequins v Saracens, which had a slightly higher peak of 230,000.
The viewing figures for Aviva Premiership Rugby's first month on BT Sport are up by 90 per cent and have been hailed as "an outstanding success”.
In the first five rounds of Aviva Premiership Rugby, BT Sport showed 16 live games and recorded an average viewing which is almost double that of a year earlier when the league was being shown on ESPN and Sky Sports.
Dominic Hayes, Premiership Rugby commercial director, said: "We are delighted with these viewing figures for Aviva Premiership Rugby as they show the huge appeal and potential of the competition.
"TV viewing figures are a great barometer of the health of a competition like Aviva Premiership Rugby. We are delighted to see all of the hard work delivering outstanding success.
"We are committed to bringing fans closer to the action and at Premiership Rugby we have been delighted with the partnership so far, not just for live matches but also for the midweek show - Rugby Tonight.
"The coverage innovations like the dressing room cameras and in-game interviews have been welcomed by our supporters."
Simon Green, head of BT Sport said: "Aviva Premiership Rugby is extremely important to us. We show live games every Friday, Saturday and Sunday and so we are showcasing the very best of the action.
"Saturday's are a big day of live sport for us and we think that showing an exclusively live Barclays Premier League game followed by an Aviva Premiership Rugby Game provides a great afternoon of live sport for our viewers. We want to grow the popularity of club rugby and I'm delighted to see that it's working."