Enzo Maresca backed Nicolas Jackson as his first-choice striker at Chelsea on Friday despite Christopher Nkunku's match-winning impact against Bournemouth last weekend.
Nkunku came off the bench to net late on in a 1-0 win, securing just Chelsea's second win in four Premier League games since Maresca took charge.
Jackson has started all four games and extended his contract at Stamford Bridge to 2033 last week.
The Senegal international scored 17 goals in his debut season with the Blues, but was also guilty of missing a number of big chances.
"For me, in this moment, Nicolas is our striker, I don't have any doubt," Maresca said at his pre-match press conference ahead of Saturday's trip to West Ham.
"Because of the way he is working day by day and the way he is working on the ball and off the ball.
"In this moment, we are very happy with Nicolas. In terms of numbers, last season and this season, it's already important numbers."
Nkunku's first season after a £52 million ($69 million) move from RB Leipzig was disrupted by a serious knee injury.
The French international has scored three times in six appearances under Maresca and the Italian insisted he will get his chance to shine as he hit back at criticism of Chelsea's bloated squad.
"As a left winger, we have Jadon (Sancho) and Misha (Mykhailo Mudryk). As right wingers, we have Noni (Madueke) and Pedro (Neto). As attacking midfielder, we have Cole (Palmer) and Joao (Felix). As a nine, we have Nkunku and Nico.
"There are not so many players, we have two players in each position."
Maresca, who led Leicester to promotion from the Championship last season, has had a whirlwind start to his time in west London since replacing Mauricio Pochettino.
After a troubled pre-season tour to the United States and chaotic transfer window of comings and goings, he then had to face questions of reported infighting between Chelsea co-owners Todd Boehly and Behdad Eghbali.
But on the field things are coming together for the Italian.
Chelsea's only league defeat so far came against champions Manchester City, while they overcame Swiss side Servette to reach the group stages of the UEFA Conference League.
"We are ahead of where I expected, to be honest," added Maresca.
"Since I have started, the players have been open-minded and they are taking in all of the information."