Renshaw edges out Cavendish in Exmouth
Renshaw, who has so often played Cavendish's lead-out man, stayed in front of Cavendish during the sprint finish although it was unclear whether the Brit decided to allow his team-mate win the stage after a day full of aggressive riding.
There were lots of attacks during the stage and the last of those, from Damien Gaudin of Team Europcar, was only reeled in three kilometres from the finish.
Lars Boom (Rabobank) finished safely in the peloton to retain his overall lead of the race.
"We started out with a thirteen rider break today," said HTC sport director Allan Peiper, "They had a maximum gap of six and a half minutes, and a few of the main contenders for the GC were up there working hard.
"Rabobank did a lot of work to reel them in but cracked toward the end, and with the help of a few more teams we were able to bring the break back a bit.
"Somewhere between thirty and forty kilometers to go the break started attacking and fell apart, and by twenty to go, the peloton was back together with our boys up front.
"The guys did a great job controlling the front until Bernie [Eisel] got a flat. The roads were extremely narrow and without radios it took too long for us to get a car to him, so he was effectively out of the race."
"On the final kilometre, Renshaw was piloting Cavendish perfectly for the win," Peiper continued, "But in the last corner, Cav backed off and Renshaw came out of it in the lead, so he hammered toward the line and finished just ahead of Cavendish.
It is Renshaw's third win of the season after his stage four and overall wins in the Tour of Qatar.
Stage six on Friday sees the riders travel from Taunton to Wells.
The race concludes in London on Sunday.