Luke Beckett headed Huddersfield into Monday's FA Cup fifth-round draw at the expense of his former club Oldham.
Huddersfield's Beckett celebrates scoring against his former club
Beckett headed home Nathan Clarke's long throw-in to put the Terriers ahead while at the other end a save from Matt Glennon kept out Dean Smalley's header.
Oldham came back strongly and Stefan Stam fired over from 20 yards but genuine goal-scoring chances were rare.
Beckett could have made the game safe but failed to connect with Danny Schofield's low ball at the death.
Although a strong wind was blowing in Oldham's favour, Huddersfield started the match brighter and were rewarded with Beckett's near-post header.
The former Latics man celebrated by directing a clenched fist at the travelling fans to show where his allegiance now lies.
Oldham responded and Smalley just failed to connect from six yards out before his firm header drew a brilliant save from Glennon.
Huddersfield's debutant defender Robert Page repelled wave upon wave of attacks after the break but the goal did not look like coming for the home side.
The Terriers always looked a threat on the break and Phil Jevons wasted a scoring chance when he chose to lay the ball off to Beckett.
The former Latics striker was given another chance to double Huddersfield's advantage but failed to reach the ball in time. As it was he had already done enough to see the Terriers through.
Oldham: Crossley, Eardley, Trotman, Stam, Hazell, Allott, Kalala (Wolfenden 76), McDonald, Taylor, Smalley, Davies.
Subs Not Used: Pogliacomi, Black, Lomax, Alessandra.
Booked: Taylor, Trotman.
Huddersfield: Glennon, Sinclair, Page, Nathan Clarke, Williams, Collins, Holdsworth, Worthington, Schofield, Beckett (Mirfin 90), Jevons (Kamara 83).
Subs Not Used: Smithies, Racchi, Berrett.
Goals: Beckett 10.
Ref: Graham Laws (Tyne & Wear).
BBC Sport Player Rater man of the match: Huddersfield's Luke Beckett 8.00 (on 90 minutes).
Please note that you can still give the players marks out of 10 on BBC Sport's Player Rater after the match has finished.