Ewan (Lotto Soudal) was narrowly defeated by Sam Bennett (Deceuninck-Quickstep) and later lamented he hadn't started his sprint a bit sooner.
The Australia had managed to navigate his way through the tension of the stage to the sprint finish, after a near-perfect leadout from Michael Mørkøv.
“It was super stressful,” said Ewan of Stage 10.
“All the way from the start there was so much stress from the GC teams. They obviously want to keep their rider out of the wind and out of the splits.
"I stuffed up my sprint a little bit and waited a bit too long and didn’t have enough room in the end to come round him."
McEwen, a triple winner of the Tour de France's green jersey, analysed his countryman's sprint via the SBS touchscreen.
"There was a fraction of hesitation but that's not what lost it for Ewan," McEwen said.
"He was coming but they were so close to the line and Sam Bennett still had half a wheel in front of Caleb Ewan."
"Tomorrow (Stage 11) is going to be another bunch sprint tomorrow though ... I think Caleb will be ruing he didn't take off earlier today but he'll get another crack tomorrow.