Yarmolenko played the first 45 minutes of the tie after signing from Borussia Dortmund on Wednesday.
Pellegrini believes the 28-year-old will prove to be a popular addition to his squad with the West Ham fans.
He said: “West Ham, throughout history, have always been a team that likes to play offensive football, and to score goals. Yarmolenko is a technical player.
“I think all the players we are bringing in, including Yarmolenko,have those same characteristics. Technical players that will score goals."