Castroneves started 18th after an untimely red flag during the first qualifying round on Saturday denied him time to record a hot lap.
On Lap 24 of the race, Castroneves advanced the Hitachi Team Penske Chevrolet to seventh place after avoiding a multi-car incident in Turn 1 after a restart.
Castroneves was in 16th place on Lap 39 when the Hitachi Chevrolet was hit from behind by Sebastien Bourdais during a five-car incident in Turn 1, which damaged his front wing and right rear tire.
After dropping to 22nd due to three consecutive pit stops, Castroneves used his remaining push-to-pass overtakes to rally for a 13th-place finish.
With the result, Castroneves fell from first to third in the series standings, now 20 points behind Takuma Sato.
Helio Castroneves - On how the race went... “The Hitachi car was pretty good all day and for most of the race we were getting the breaks we needed with the caution flags to move up the field. Unfortunately, things got a little anxious on the restart and we got some damage to the front wing and rear tire.
Even then, I thought we could make a move but it was tough to talk strategy with the lack of radio communication in many places.”
On what happened on the incident in turn 1: “It’s unbelievable what goes on there, people are just hitting everyone. You have to look to the front as much as the corner and it’s frustrating because you know you can’t avoid it. But that’s what makes Sao Paulo such a great race.”
Power began the race in the 22nd position after the same red flag that caught out Castroneves in qualifying also affected the three-time Sao Paulo race winner.
Power started on primary Firestone Tires and progressed quickly through the field, moving up 10 positions to 12th place by Lap 16.
On Lap 18, while running 12th, the Verizon Team Penske Chevrolet suddenly caught fire and was damaged beyond repair.
Sunday’s race marked the first time in four starts at Sao Paulo that Power did not end up in Victory Circle and the first time he has failed to finish at a road or street course event since Toronto in 2011.
With the 24th-place result, his worst since Fontana in 2012, Power dropped 10 positions in the IZOD IndyCar Series standings to 18th place. It marks his lowest position in the championship since he joined Team Penske in 2009.
Will Power - How he felt at the start of the race... “The Verizon Chevrolet was such a great car today – the guys really had it tuned in. It felt like we were passing a car every lap. I thought we were going to be able to make the moves we needed to make it a great race.”
On what happened with the fire...“We must have burned something with the gear shift because it stopped shifting. We don’t know what happened; I had no real warning unfortunately.”