Conor O'Shea, the Harlequins director of rugby, and Rob Baxter, Exeter's head coach, both expressed dissatisfaction with referee Sean Davey after Quins claimed a 19-13 victory in the Aviva Premiership on Saturday.
Nick Evans converted Mike Brown's try and the fly-half slotted four penalties to help Quins prevail but the aftermath of the match was dominated by discussion of Davey's display.
"The breakdown was an absolute nightmare," O'Shea declared. "Players not rolling away after tackling, players going over the top. It can only be a matter of a second lost, but in rugby those seconds are priceless and can cost you an attacking opportunity. "
Baxter went further and even approached Davey at the final whistle to express his indignation. "I spoke with the referee and told him that I felt there were inaccuracies in the game that I shall look at further during the week before making my report," Baxter said.
"Frankly, I am not happy with the way the game was officiated. I am massively frustrated. Not with our guys because they did everything asked of them. But there are certain elements of a rugby game over which you have no control."
Jim Mallinder, Northampton's director of rugby, offered high praise for Vasily Artemyev after the winger touched down twice to help Northampton defeat Newcastle 44-15.
Artemyev, who scored a try for his native Russia in a Pool C defeat to Ireland at the World Cup, took his try tally to six from three matches since arriving at Franklin's Gardens.
"He's settled in really well and seems to know the way to the try line," Mallinder said of the 24-year-old. "He'd stood out playing for Russia, who were not always winning games and getting on the front foot, but he had the knack of scoring and looking good."
Tom May and England's Chris Ashton also scored two tries each for Northampton, with team-mate Ryan Lamb providing three conversions and two penalties, consigning Newcastle to a defeat that ensures they remain bottom of the table.
"I think Tom was determined to do well against his old club but Chris's tries were just a bonus," added Mallinger. "All the hard work was done up front before that."