Their goalless draw with Everton helped Liverpool to a 17th clean sheet of the season.
The Reds have kept four successive shutouts in a run that has earned Robertson and Virgil van Dijk (£6.6m) places in the top-five scoring players in FPL.
The left-back sits fourth overall on 168 points, six ahead of Van Dijk, and eight more than the top-scoring forward, Sergio Aguero (£11.8m).
When it comes to value, in terms of FPL points per million (ppm), Liverpool's defence boasts the top three outfield players.
Robertson leads with 24.7 ppm, ahead of Van Dijk's 24.5 and the 22.4 of Trent Alexander-Arnold (£5.4m).
The Scot's all-round game has been key to his appeal in Fantasy.
His nine assists are more than any other defender, as are his 24 bonus points.
And the 24-year-old is also closing in on the all-time points record for a defender in a single season.
That was set by Joleon Lescott, who produced 196 points for Everton in 2007/08.
Robertson has averaged 6.2 points per match for the Merseysiders and still has nine fixtures remaining.
Should he maintain his current form, he looks set for a record-breaking season in FPL.