Left-handed Cook (batting 87) once again led from the front and shared a 110-run stand with Pietersen (62 not out) to put England in a promising position going into third day at the Wankhede Stadium. Left-arm spinner Pragyan Ojha took both the wickets to fall.
England also did well not to allow India's last four wickets to add more than 66 runs when they resumed at the overnight 266 for six. Cheteshwar Pujara (135), who at last was dismissed for the first time in the series after scoring 382 runs in three innings, and Ravichandran Ashwin (68) stretched their seventh-wicket partnership to 111 runs.
Monty Panesar (5/129) trapped Ashwin in front for his fifth wicket while Graeme Swann (4/70) got Pujara stumped and cleaned up the tail.
England came out and batted with intent. They came out with a plan and applied themselves on a more trying surface here than what they encountered in Ahmedabad.
The visitors were in a spot of bother when Ojha dismissed opener Nick Compton (29) and Jonathan Trott (0) in consecutive overs to make 68 for two. But Cook and Pietersen steadied the ship with their aggressive batting.
Cook is set for another big innings after scores of 176 and 41 in the opening game. He struck 10 fours and a six and is 13 short of his 22nd Test century.
Pietersen finding form is also good news for the England. He showed why his contribution is so important to his team's chances in the fourth-match series. The stylish batsman started with a delightful cover drive off Harbhajan Singh before collecting eight more boundaries, scoring at an impressive strike rate of 72.94.
India, however, now need a breakthrough to change the course of the game as the pitch is very much receptive to the spinners. The ball interestingly turned pretty sharply in the morning, but slowed down as the day progressed.