The former Gunner completed a season-long loan switch to the Boleyn Ground on August 30, signing from Spanish giants Barcelona.
He has made four Premier League appearances for the Hammers since his arrival, starting three games, and has impressed in the new-look side put together by Sam Allardyce, despite still returning to full fitness.
Having made his debut as a second half substitute against Hull City, Song has gone on to start the last three games, of which the Hammers have won two, claiming victories against Liverpool and QPR, and unfortunately falling to a 2-1 defeat at Manchester United.
Although he has gone under the radar due to the performances of fellow summer arrivals Diafra Sakho, Cheikhou Kouyate and Morgan Amalfitano, his ability to link up the fluid play across a midfield cursed by injuries has seen him impress the Hammers faithful, and the Standard named the 27-year-old as the best signing West Ham made over the summer.
Given an A grade, the only other man to receive such high praise was forward Sakho, who has netted five goals in five games in all competitions since making his debut. Fellow striker Enner Valencia was given a B, along with Kouyate, whilst Aaron Cresswell and Carl Jenkinson have been given C grades - for solid, but not impressive starts to the season.
Song will look to cement himself as a key part of the Hammers side if they intend to fulfil their promise of fighting for European qualification this season, and Allardyce should be looking at tying the talented midfielder down on a permanent basis come the close of the campaign.