Power, driving the #12 Verizon Team Penske car, set a time of 1m00.5581s, just 0.1s faster than Scott Dixon in the #9 Target Chip Ganassi Racing car was second. Championship points leader Dario Franchitti (#10 Target Chip Ganassi Racing) car was third.
Power says that he still needs to find time in his Penske to remain at the top.
“The Verizon car is good, but we are still not quick enough,” he said.
“We put tyres on there at the end of the second practice and no one else did. We are just a bit off the pace. We still have a few things in mind to improve the car. It is great to be in Toronto, though, and really good to see all the fans.”
Qualifying will be held tomorrow at the Toronto circuit.