Both the Argentina international and his fellow striker Suarez have been in glittering form this season, although the spotlight has been on the latter in particular since Wednesday night, when he fired in four goals - including a superb 20-minute first-half hat-trick - for Liverpool in their 5-1 win over Norwich.
Those efforts mean the Uruguay frontman now tops the Barclays Premier League scoring charts for 2013-14 with 13 goals - two more than second-placed Aguero has netted.
Pellegrini is in no doubt that Suarez is a deadly forward, but last month the Chilean said he believed Aguero was behind only Barcelona's Lionel Messi and Real Madrid's Cristiano Ronaldo in terms of being the world's best player.
And at his Friday press conference to preview Saturday's top-flight trip to Southampton, when asked about Suarez, Pellegrini made it clear his view of Aguero as the Premier League's number one footballer has not changed.
"Suarez is a very important striker, but I think Sergio participates more in the game," he said.
Pellegrini has already spoken about the way he feels Aguero has been improving, making specific reference to the work he has been doing without the ball.
It is a theme he returned to on Friday when asked if he felt the 25-year-old could still get better.
"Sergio is just 25 years old, so I think of course he can improve," Pellegrini said.
"I think this year he has improved a lot in the way he works during matches.
"He has always been a top player and he has always scored goals, but I think at this moment, he has added working for the team without the ball, which is also important for him.
"I never said he was the best striker in the Premier League - I said he was the best player. Maybe there are players who are better strikers than him, but not as complete as him.
"Maybe it (his improvement) is because he is older. For me, a player has the best performances between 24 and 30 years old.
"Sergio started very young in his career and I think that every year, he is improving.
"This year, the best thing he is doing is scoring goals, but he has added to his performance the work for the team without the ball."
Along with City - 3-2 victors at West Brom, with Aguero scoring the opener - and Liverpool, leaders Arsenal, Chelsea, and Tottenham all won on Wednesday, while champions Manchester United suffered a 1-0 home defeat to Everton.
United are now ninth in the table, 12 points behind the Gunners, with all teams in the division having played 14 games.
It does not look promising for the Red Devils' hopes of defending their crown, but when asked if he thought United were now out of the title race, Pellegrini said: ''I think the fight for the Premier League is exactly the same.
"There are eight or nine teams that are very close in points."
City - who are third, six points behind Arsenal - had won only one of six Premier League away games this term, losing four of them, before the West Brom result.
Beating Albion was certainly a boost ahead of the Saints trip, although Pellegrini insists that even prior to the match at The Hawthorns, there had been no issues with his players' confidence regarding their ability to secure victories on the road.
''I think before the West Brom game, we didn't have any problems psychologically about winning away,'' he said.
''We were sure we were going to start winning. So then that (West Brom) was first, and now we must repeat it tomorrow.''
Pellegrini is optimistic City captain Vincent Kompany will be fine to keep his place in the team for the encounter with eighth-placed Southampton.
The defender, who has been sidelined by a thigh problem, made his first appearance since October 5 on Wednesday when he played for the whole of the West Brom game, and there have been no ill-effects reported after that outing.
Striker Stevan Jovetic, defender Matija Nastasic and playmaker David Silva will all miss out due to their calf injuries, but Pellegrini has indicated the latter of the trio could be involved in Tuesday's Champions League match at Bayern Munich.
The manager once again would not confirm whether Costel Pantilimon would be retained in goal or Joe Hart brought back in his place.