Jed Steer’s failure to punch clear a free-kick saw Evandro Goebel open the scoring for the hosts in the seventh minute.
But in the 14th minutes, the hosts’ poor defending gave room for Tommy Elphick, making his first start for his team since January 1, to head in the equaliser unchallenged from a corner kick.
And in the second half, Elmohamady and Alan Hutton scored to propel Steve Bruce’s men to an away victory.
The outcome of the clash took them to the second spot in English second tier table.
Aston Villa continue their campaign as they entertain Wigan Athletic at Villa Park on August 11, and Elmohamady will hope to impress with another decent shift.
FT: #HCAFC 1-3 #AVFC— Aston Villa FC (@AVFCOfficial) August 6, 2018
A fine start to the season as we come back from behind to take all three points. Tommy Elphick, Ahmed Elmohamady and Alan Hutton on the scoresheet. Superb noise all night from the travelling Villans. Get in there!! 👊 #PartOfThePride #AVFC pic.twitter.com/oSLIZAQeuy