Riding over a 43.8kilometre course, Impey stopped the clock in a time of 52min 37sec in hot conditions. He finished two minutes 17seconds faster than Ryan Gibbons (Dimension-Data) and more than six minutes in front of local Rohan Du Plooy.
“It is always nice to win the time trial, every year there is always a bit more pressure," Impey said. "I was confident after Down Under that I would come here and be able to do a good ride, it was really hard and I am super happy with it.
“I started off quite fast and hard but kind of blew up a little bit towards the end, but I think I still paced it quite well.
“It was so hot compared to other years and I think the competition felt that. It was around 36degrees at two-thirty in the afternoon.”
Next for Impey is the road race, which he has never won and is desperate to add to his list of achievements.
“The road race is something I have never won so there is always pressure from myself to try and win," he said. "It is important to try and win it eventually, but it is hard, I know the odds are stacked against me with all the teams and their numbers.
“I am hoping to carry some form from Down Under and hopefully do something special on Saturday, we will see, it is always difficult to say what will happen.
“Condition-wise I am ready for it, it is quite a short race so I think it should be quite aggressive.”