Two first-half goals from Joe Pritchard and Connor McBride sent Dale into the break with a comfortable lead before substitute Tyler Smith flicked home to complete a superb away performance.
The Head Coach brought in new signing Charlie Waller for his Dale debut, with Galvin and Ian Henderson, for his first league start of the season, also into the chosen eleven.
It was an attacking start for McNulty’s men as within two minutes, Ryan Galvin on the left spotted his namesake Ryan East in space but the low ball was collected by Luke Hutchinson.
The two Ryan’s then linked up again with the midfielder this time going for goal which forced the Altrincham shot-stopper into a fine save to his left after a deflection.
Debutant Waller carried the ball from one end to the other shortly after, however his low effort was held.
Dale’s bright opening got the goal it deserved on 17 minutes, Kyron Gordon showed his crossing ability to pick out Henderson who nodded it back into the path of Pritchard sliding in for his first goal.
It was almost a quickfire double when Harvey Gilmour latched onto Pritchard’s cutback and fed in Henderson in an onside position. The record-goalscorer swivelled and shot but unfortunately it drifted narrowly wide of the far upright.
Hutchinson was called into action again from East as he had the freedom of the Alty half and tried his luck with a parried save to the ‘keeper’s left following.
Dale kept pushing and found a second with a fabulous team goal. Tobi Adebayo-Rowling and Gordon somehow kept the play alive in a tight area with the number two able to get in behind and tee up McBride who sent a wonderfully lofted attempt into the far corner for his fourth of the campaign.
Ollie Crankshaw gave the home side a slight glimmer when he put the press on Nathan Broome with the ball spinning away from the goalline and into the grateful arms of the Bolton Wanderers loanee.
A scramble in the area ensued in the final action of the first-half, Galvin and Henderson both unable to convert with the loose ball rolling off target.
Altrincham regrouped well in the second period with two half chances straight away before a low driven effort from Lucas Weaver was tipped round the post by Broome.
The number 25 was kept busy as within the space of two minutes he tipped over both Adam Marriott and Tom Crawford’s close-range efforts to preserve his second clean sheet, the second from point blank range.
Smith was introduced as part of a triple change and made an instant impact with 15 minutes remaining, scoring with his first touch after another impressive team move which included an outrageous flick from the goalscorer McBride in the build-up.
East was at the heart of the Dale attacks again, he finally thought he had netted but Hutchinson got down low well to deny him.
Dale saw out the final moments to retain top spot and earn another clean sheet on the road.
Altrincham XI | Hutchinson, Baines (c), Crankshaw, Marriott, Knowles (77′ Ward), Kosylo, Weaver (56′ Reddin), Crawford, Golden, Jones (77′ Gale), Sassi.
Unused subs | Beddow, Cooper, German, Kirk.
Dale XI | Broome, Gordon, East, Ebanks-Landell (c), Gilmour (71′ Pettit), Adebayo-Rowling, Pritchard (71′ Burger), McBride (84′ Rodney), Waller (77′ Moss), Galvin, Henderson (71′ Smith).
Unused subs | Tutonda, Amantchi.
Scorers | 17′ Pritchard, 34′ McBride, 75′ Smith.
Attendance | 3332 (1056 away).
