Murray was ruthless as he raced to a another impressive victory, saving energy for the doubtless tougher tasks to come, starting today against the winner of last night's match between Tomas Berdych and Tommy Robredo.
In a tournament that seems to be throwing up a storyline each day, Murray is getting the job done in double-quick time. Having needed just 70 minutes to oust Mikhail Youzhny in round one, the world No.2 was even more ruthless against world No.36 Benneteau, taking 69 minutes.
As with Youzhny, Murray was dialled in from the start, making very few errors and forcing the Frenchman to go for too much. When Benneteau did manage something decent, Murray was more than a match for him, swatting winners on both sides.
With his flashy style, Benneteau has troubled many of the top players in the past, but Murray was too solid and simply too good.
A break of serve in the opening game set the tone and Murray broke again two games later on his way to a 4-0 lead, a margin he maintained through the rest of the set.
He stamped his authority on the second set by again breaking in the first game and never looked in trouble as he cruised through to the last eight, three wins away from a third Cincinnati title.
The Ohio city of Mason is about 25 miles outside Cincinnati but such has been the drama this week that the crowds have been flocking to the Lindner Tennis Centre.
The announcement by Wimbledon champion Marion Bartoli that she is retiring from the sport was a real shock and yesterday, Roger Federer began his match with Tommy Haas looking like his own last days as a player might not be too far away.
The former world No.1 and winner of a record 17 grand slams played a woeful first set, missing simple forehands, easy volleys and looking a step slow as the 35-year-old Haas raced through it 6-1.
An early break in the second put him further ahead and it was only when Federer broke back for 4-4 that the Swiss looked like making a fight of it. Once he had taken the set 7-5, Federer looked a changed player and he broke for 5-3 before serving out for a 1-6, 7-5, 6-3 win that could be significant after a challenging year to date.
Having experimented with changing to a larger-headed racket in the last month, Federer returned to his old racket and, having shaken off a back injury, he looked delighted and relieved to get through.
It will not get any easier for him though. In the next round he will face the winner of the match between Rafael Nadal, fresh from his Montreal win, and Grigor Dimitrov of Bulgaria.
Top seed Novak Djokovic, meanwhile, is looking mightily impressive, crushing David Goffin of Belgium 6-2, 6-0. Victory for the world No.1 would complete a full set of Masters 1000 titles, a remarkable achievement by anyone's standards.
n Jo-Wilfried Tsonga, the world No.8 from France, will miss the US Open after failing to recover from a knee injury.