The daughter of Dubawi has been a revelation this summer, winning at Thirsk, Lingfield and Folkestone.
This was a big rise in class but she coped well, travelling strongly before coming through to lead with a furlong to go.
She drifted left inside the final furlong but was always doing enough to win by a length.
Roger said: "You don't get many who win four races ever let alone in a row but when a filly gets on a roll they can take some stopping.
"This filly loves summer firm ground and always gives her all."
As for the future Lanansaak looks to have a bright one based on her convincing win on debut in the 7f fillies maiden.
Sheikh Hamdan's filly overcame greeness under Paul Hanagan but showed an impressive turn of foot to put the race to bed and win by a length and a half.
Roger added: "She has always been a filly that we have liked and she has done it nicely. We'll probably look to step he up to a mile now."