Jake Gordon scored a hat-trick of tries as the Waratahs produced a stunning first half in a record 45-12 win over the Reds on Saturday.

Scrum-half Gordon crossed for three of his side's five tries before the break, Jack Maddocks and Alex Newsome also touching down during the onslaught at the Sydney Cricket Ground.

Will Harrison converted them all following a fifth-minute penalty that had opened the scoring, his boot helping the Tahs open up a stunning 38-0 lead midway through the Super Rugby AU contest.

Tom Horton added to their advantage with a close-range finish in the 52nd minute, this time Ben Donaldson adding the extras in wet conditions following steady rain.

Jack Hardy finally grabbed the visiting Reds' first points with a try soon after, while James O'Connor went over in the final move of the game for a score the fly-half also converted.

However, despite the late points, the final margin of victory for Waratahs is the biggest in a Super Rugby meeting between the sides.