The Giants stay top of the table after Warrington lost at Hull KR but there was little else for the home fans to cheer. Huddersfield sorely lacked leadership in the absence of their skipper Danny Brough, who pulled out through illness, and never recovered from a shocking start in which they conceded two tries in the first nine minutes.
Joe Wardle, David Faiumu and Shaun Lunt went over for the Giants but they were always playing catch-up. Meanwhile, Sammut rounded up his performance with a drop-goal as well, while Chev Walker, Danny Addy, Brett Kearney, and substitute Adam O'Brien also notched tries for the visitors.
Wigan Warriors survived an almighty scare before maintaining their excellent recent record against Castleford Tigers with a tense 28-22 victory at the Wish Communications Stadium.
The Cherry and Whites came into this match having won seven of their last eight meetings with Castleford, the exception a 22-22 draw in June 2011. On that occasion Wigan relinquished a 22-4 lead and they did likewise this time around as a wonderful score from Jamie Ellis and two from Justin Carney revived the hosts.
Ben Flower, Pat Richards and Chris Tuson had earlier given Wigan the lead. Jake Webster pulled a try back but the visitors stretched out further thanks to Michael Mcllorum's effort early in the second half. Rangi Chase struck the post with a late drop-goal attempt, but Tuson had the final say when crossing for his second try in the last minute.
The Tigers therefore suffered a first home defeat of the campaign - but can take plenty of heart from their rousing second-half fightback.
Hull KR produced their best 80-minute performance of the season to beat Warrington 26-12 in their match at MS3 Craven Park.
Winger Dave Hodgson scored two of his side's four tries as the Wolves tasted their first defeat of the season. Hodgson's efforts came around a third Rovers try scored by Cory Paterson, with Alex Brown adding gloss to the win by going over in the final minute.
Wolves showed plenty of promise, not least when Stefan Ratchford and Ryan Atkins scored first-half tries with Brett Hodgson successfully converting both, the latter giving them a 12-6 lead. But it proved in vain as Michael Dobson kicked the third of his five goals on 63 minutes to give Rovers a lead they did not give up.