Power second in Indycar Toronto practice

Defending Indycar champion Simon Pagenaud has pipped Australian Will Power in Friday's second practice session ahead of this weekend's race in Toronto.

Will Power is fourth in the Indycar drivers' standings in 2017. (AAP)

Australian Will Power has clocked the second-fastest time in Friday's second practice session for Indycar's Toronto street course race.

Defending Indycar champion Simon Pagenaud set the fastest time of the day's two sessions, clocking 1min 0.2573sec.

His teammate Power, who won last year's Toronto race, set a time of 1:00.4844.

The top three drivers were all from Team Penske with championship leader Scott Dixon of New Zealand, third in 1: 00.6253.

Practice continues on Saturday before qualifying later that afternoon.

The race is Sunday.