The little Argentine was making his first Premier League start since a summer loan move from the footballing backwater that is the UAE league.
The Hammers haven't won at Anfield for 52 years. But they were ahead after just over a minute today, Lanzini slotting home inside the box after Aaron Creswell's cross-cum-shot following a poor clearance from Martin Skrtel.
It was the dream start for West Ham and things got even better midway through the half when skipper Mark Noble slotted home from the edge of the box after great work from Lanzini again.
The diminutive attacking midfielder chased Dejan Lovren on the right and kept the ball alive, forcing Lovren to give away possession on the edge of his own box. Lanzini then advanced into the area and his attempt to tee up Diafra Sakho was only half cleared before Noble came striding onto the ball to stroke home.
It was not just Lanzini's work going forward on the break that proved invaluable.
His dogged determination and tracking break thwarted Liverpool attacks time and time again and he robbed Phillippe Coutinho of the ball on at least five occasions. At 2-0 up, West Ham are on the verge of ending their Anfield hoodoo which dates back to when the Beatles were number one in the 1960s.
But they will know from their own match against Bournemouth last week - where they trailed 2-0 at the break and pulled it back to 2-2 in eight second-half minutes - how fragile that scoreline could be.
Bilic's tactics have been spot on but West Ham are bound to tire due to the sheer amount of hard work they are putting in to close the hosts down all over the pitch. And the bench is very youthful with West Ham's squad stretched to the absolute limit at the moment.