The Rocks notched their third win over Sussex opposition in six days in a game that will swiftly be forgotten in terms of entertainment value.
A goal on 68 minutes from in-form Dan Thompson was enough to secure the three points.
Early on, Kane Wills’ curling cross from the left flew beyond Thompson in the box and into the grateful arms of United keeper Daniel East.
Terry Dodd set up Ollie Pearce down the left and his dipping cross was just too much for Dodd as East gathered at the second attempt.
Hastings’ Zac Attwood came off injured on nine minutes. The ex-Rocks player looked in pain as he headed straight for the dressing room. His replacement was Bailo Camara.
A cross from Alassane N’Diaye was awkward for the Rocks defence but Camara couldn’t convert it.
Daryl Wollers mis-controlled a ball on the left, allowing N’Diaye through on goal but Craig Stoner blocked his attempted shot at the near post.
The Arrows began to pile on some pressure and N’Diaye struck a shot that bounced wide of the post.
Ellis’ cross for Gareth Williams was cut out by Dan Kempson but Hastings looked the livelier side nearing half-time.
Freddie Warren had perhaps the best chance of the half when he cut inside before hitting a shot with his left boot which spun disappointingly wide – spurring ironic cheers from the Nyewood Lane crowd.
Stoner had to gather a cross a minute into the second half and then deal with a high looping strike which looked like a halfhearted attempt on goal from long-distance by Williams.
Elliott Cox sped past Wollers on the left to get a cross in. Ellis headed the ball towards goal, but it just flew narrowly over.
Pearce’s header from Kempson’s cross forced a save from East.
Camara ran through on the hour only for Stoner to close him down - then Stoner bravely blocked a shot from N’Diaye after he beat his marker to get in behind the defence.
On 65 minutes Dodd was replaced by Connor Cody.
Two minutes later, Wills fed Crane, who hit a low shot that was blocked by the goalkeeper, The rebound was deflected for a corner.
The resulting corner was taken by Wills and found Thompson, who powered a header low into the net.
Stoner sliced a clearance out for a corner, from which player-manager Sean Ray sent a header narrowly wide.
A great touch from Thompson allowed him to pass to Wills, but he was denied by East.
Williams scooped the ball over the bar from inside the box on 84 minutes as Hastings failed to draw level. The same player hit a shot from 30 yards but Stoner saved easily with a minute left.
ROCKS: Stoner, Stockford, Tuck, Crane, Warren, Wollers, Kempson, Wills, Thompson, Dodd, Pearce. Subs: S Pearce, Cody, Morey, Marzetti, Boyle.
The Rocks are next in action at home to Canvey Island on Tuesday evening.