The midfielder set us on our way, scoring the opener after seven minutes, latching onto a great throughball from Oscar Bobb before rounding the keeper and scoring.
After Carlos Borges doubled our lead, Robertson put us out of sight with a sublime turn and nutmeg on his opposing defender, giving him space to finish into the bottom corner.
Borges and Dire Mebude would complete braces as the EDS ran riot against previously unbeaten Arsenal to move to the PL2's summit.
Injury and setbacks means this was Robertson's first competitive 90 minutes in almost two years, and the 19-year-old was delighted with his and the team's display.
"We just practice in training," he said of his first goal.
"The in-behind run and Oscar knows how I run, how I play and I knew he would get it there."
On his second goal, he added: "It was a nice little nutmeg and then a great finish as well, it was a great win for the lads and two goals is class for me.
"They are a good side and they have been for the whole season and for us to get the win over them is really good."
Watch Alex's interview in full via the video above...