"It's been a good week for us, gaining four points against Manchester United and Arsenal, both away games," Chilean Pellegrini told reporters. "We had clear chances in the first half to win it and were a bit unlucky.
"Arsenal had a better second half but in the first half we had four clear chances and maybe we could have finished the game before halftime.
"The four teams will drop points between now and the end of the season. It's always very difficult at the end of the season because sides in danger of relegation will fight to the last," said Pellegrini.
Leaders Chelsea have 69 points with six matches to play but Liverpool (68) can go top by winning at home to Tottenham Hotspur on Sunday.
City are third on 67 points but have played two games fewer than Chelsea. Fourth-placed Arsenal have 64 points.
Pellegrini's team dominated the opening period at the Emirates with David Silva, who scored an early goal, ruling the midfield and Arsenal rarely troubling the visitors' defence.
Arsenal manager Arsene Wenger pushed men forward in the second half and Mathieu Flamini's equaliser was just reward for a much improved performance by the home side.
The title challenge of Arsenal, thrashed 6-0 by Chelsea last week despite being top of the table for long stretches of the season, has deflated over the last eight days with the north London side gaining just two points from three games.
Wenger, while admitting the "nightmare" against Chelsea had affected his team early on against City, vowed Arsenal would "fight until the end".
"In the first half we were insecure in our own attitude because of our last two results but we controlled the second half. It was a game of quality between two good teams," said the Frenchman.
"What happened to Chelsea today could happen to anyone," Wenger added in reference to the Stamford Bridge side's 1-0 defeat at lowly Crystal Palace.
"It shows we absolutely have to fight until the end of the season because everybody can beat everybody. All of us have to be careful and all of us have to be consistent.
"Mathematically we are still in there but it's not in our hands. We have to look above us and behind us as well," said Wenger.
Arsenal, in the final Champions League spot, are seven points clear of Everton in fifth place but Roberto Martinez's team have played two fewer games. (Editing by Tony Jimenez)