But on 83 minutes Pierre-Emerick Aubameyang found room at the back post and deftly chipped across the six-yard box for Torreira to acrobatically volley in.
It was a rare moment of quality from the hosts, who failed to create regular chances, despite Alexandre Lacazette having a goal disallowed for offside shortly before the interval.
The France striker was replaced at half-time, with a slightly improved Arsenal scoring their 26th second-half goal of the season to extend their unbeaten run to 21 games in all competitions.
The Gunners are third, a point in front of rivals Tottenham, who face Leicester at 19:45 GMT, with Chelsea two points further back before their match at home to Manchester City at 17:30 GMT.
Arsenal manager Unai Emery has now made 14 substitutions at the break in 16 league games this season, with Henrikh Mkhitaryan and Alex Iwobi replacing Lacazette and Stephan Lichtsteiner here.
Once again the Spaniard’s willingness to overhaul his side’s approach paid off, with both substitutes stretching Huddersfield’s back line and ensuring Aubameyang was less reliant on dropping deep to receive the ball.
The Gabon striker was frustrated in the first half – his only telling contribution narrowly diverting Granit Xhaka’s cross wide on 28 minutes – as he failed to link up effectively with Lacazette, who slipped when unmarked in the area and shot over the bar moments after Aubameyang’s miss.
Lacazette then rounded Lossl to slot in after running onto Mathias Jorgensen’s poor back pass but he was judged offside from Aubameyang’s initial header on.
That was one of few flurries of promising play from Arsenal, the other coming just before the goal as Sead Kolasinac started to get in behind down the left.
Even then it took a sequence of sublime skill for Arsenal to find a way through – Matteo Guendouzi finding Aubameyang with a well-judged cross-field pass, the striker touching it away from his man and turning to cross and Torreira applying a sumptuous finish.
It was indicative of Arsenal this season – flawed but fun. They may not be able to rely on these second-half surges and impact substitutions for the whole season but there is plenty of grit and skill in this team.
