Liverpool led a hard-fought encounter at Vicarage Road 1-0 heading into the final 15 minutes, courtesy of Mohamed Salah’s breakthrough.
Having been assigned to set-piece duties by the boss before kick-off, Alexander-Arnold took charge when the Reds then earned a dead-ball situation 25 yards from goal.
Rightly so, too.
The defender, whose first goal for the club was a free-kick at Hoffenheim at the start of last season, thumped a swerving shot into the top right corner to give his side a welcome cushion on the scoresheet.