Saracens started with a brace from Chris Ashton before Samuela Vunisa also touched down to give the hosts a 20-6 lead at half-time
After the break, Vunisa touched down his second before Alex Goode, Mike Ellery and Jamie George also chipped in with five-pointers
Fetu’u Vainikolo scored a consolation try for the visitors
Ashton then completed his hat-trick late on with try number eight for Sarries
Chris Ashton touched down a deserved hat-trick as Saracens maintained their 100 per cent record in Pool 1, edging towards the knockout rounds of the Champions Cup with an emphatic bonus-point victory over Oyonnax at Allianz Park on Saturday.
The warm sunny day was perfect for festive rugby and the hosts, despite some sloppy mistakes, ran rampant in the first half, with Chris Ashton touching down a brace before Samuela Vunisa crossed for Sarries third on the edge of half-time to give the London club a 20-6 lead at the break.
Owen Farrell converted one of the three scores while knocking over a single penalty to complete the hosts opening 40 total.
Vunisa grabbed his second three minutes after the restart before Alex Goode followed up his man of the match display against Oyonnax in the reverse fixture last weekend with another special score.
Winger Mike Ellery then burst over to touch on his first Champion Cup start before Jamie George ran in try number seven.
Fetu’u Vainikolo raced in to score a consolation try for Oyonnax after intercepting a wayward pass before Ashton completed the games scoring with his third try of the afternoon.
Saracens weathered early pressure from the French visitors Mike Ellery, who was making his first Champions Cup start, almost opened the try-scoring for the hosts after 10 minutes, but the former England sevens man’s heel had brushed into touch.
Two minutes later though Sarries wouldn’t be denied as Ashton crossed for his first try of this season’s competition. The winger, who powered through two attempted tackles to dive over in the right corner, finished off an excellent flowing move after receiving a well-weighted pass from Brad Barritt. Fly-half Farrell then added the touchline conversion, 7-0.
Regis Lespinas stepped up for Oyonnax soon after to cut the deficit to four points from the tee, but Farrell re-established the hosts seven-point lead with a simple kick from in front of the posts after 25 minutes.
Ashton was denied his and Sarries second for a forward pass soon after as the French visitors continued to defend resolutely against the relentless hosts.
However, just shy of the half-hour Ashton did get his brace. A wonderfully weighted kick through from Farrell found the winger in acres of space with him diving over in the corner once again. This time, Farrell dragged his attempted conversion wide, 15-3.
An error off the kick off quickly allowed Lespinas to kick his second penalty of the game, but Saracens would extend their lead on the edge of half-time as Vunisa forced the ball down following a powerful lineout drive. Farrell again though was unable to add the extras as the hosts took a 14-point lead into half-time.
Another driving maul three minutes after the break, touched down once again by number 8 Vunisa between the posts, secured Saracens the bonus-point and gave the hosts total control of the game. Farrell added the simple conversion, 27-6.
Fullback Goode then backed himself, weaving through a number of Oyonnax defenders on a world-class solo run to score try number five for Sarries after 49 minutes. Farrell again added the simple conversion to open up a comfortable 28-point lead.
Ellery then went over three minutes later after picking up a loose pass to run almost the length of the field to dot down untouched under the poles as Saracens continued to run rampant with Farrell again converting, 41-6.
Jamie George then ran a wonderful line to receive a perfect pass from replacement fly-half Charlie Hodgson to dive over for try number seven between the posts on the hour. Hodgson then knocked over the extras.
Fetu’u Vainikolo though did grab the French visitors a consolation after 66 minutes when he intercepted Hodgson’s pass to storm in untouched from around half way with Rory Clegg adding the extras, 48-13.
With England’s upcoming Six Nations tie with Scotland firmly on the mind, Ashton grabbed his hat-trick with five minutes to go after he pounced on a kick through from Richard Wigglesworth. This resounding win all but seals a quarter-final place for Saracens, in a season where they not only look to defend their Aviva Premiership crown; but also look to become champions of Europe for the first time.
MAN OF THE MATCH
Saracens: Chris Ashton
Saracens: 15 Alex Goode, 14 Chris Ashton, 13 Duncan Taylor, 12 Brad Barritt (c), 11 Mike Ellery, 10 Owen Farrell, 9 Neil De Kock, 8 Samuela Vunisa, 7 Kelly Brown, 6 Jackson Wray, 5 Maro Itoje, 4 Jim Hamilton, 3 Petrus Du Plessis, 2 Schalk Brits, 1 Mako Vunipola
Replacements: 16 Jamie George, 17 Richard Barrington, 18 Juan Figallo, 19 Michael Rhodes, 20 Will Fraser, 21 Richard Wigglesworth, 22 Charlie Hodgson, 23 Ben Ransom
Oyonnax: 15 Florian Denos, 14 Daniel Ikpefan, 13 Guillaume Bousses, 12 Uwa Tawalo, 11 Fetu’u Vainikolo, 10 Regis Lespinas, 9 Julien Blanc, 8 Florian Faure, 7 Pedrie Wannenburg, 6 Valentin Ursache, 5 Geoffrey Fabbri, 4 Leon Power, 3 Marc Clerc, 2 Jeremie Maurouard, 1 Laurent Delboulbès
Replacements: 16 Jody Jenneker, 17 Stan Wright, 18 Horace Pungea, 19 Viliami Maafu, 20 Thomas Bordes, 21 Arthur Aziza, 22 Rory Clegg, 23 Vincent Martin
Date: Saturday, December 19
Venue: Allianz Park
Kick-off: 13:00 GMT
Referee: George Clancy (Ireland)
Assistant Referees: Peter Fitzgibbon (Ireland), Jonathan Peak (Ireland)
TMO: Marshall Kilgore (Ireland)