Gloucester won a penalty in front of the posts straight from the kick off and Mercier took the three points.
After dominating the opening minutes in terms of possession, Mercier guaranteed good set-piece ball inside the Viadana 22 with a penalty to touch. The line-out was taken and the forwards drove the Italian pack backwards with Azam at the heart of the move. The French hooker dived for the line and took the try. Mercier converted.
Gloucester grabbed their second score four minutes later with an identical move, but this time it was blind-side forward Jake Boer who maintained possession and took the score. Mercier's trust boot added the extra.
Gloucester continued to dominate a closely fought encounter, as Viadana started to put some good phases together. Richards grabbed back the momentum with a well-judged kick that took the Italians back 30 metres.
Tindall, making his first start for Gloucester, made a powerful break after spotting the gap on half-way. His pass on the 22 was batted down by a Viadana hand and Mercier opted for the posts, but it went wide.
Foster had his first scoring chance from a cross-field kick from Mercier inside the Italian side's half. The young winger, who has been so impressive in the pre-season, cut inside before being taken to ground.
"Vickery, la, la, la, Vickery, la, la, la" came from the Shed as the Raging Bull started to make some old-style runs with the ball off the back of a line-out.
Henry Paul won turnover loose ball on the Gloucester 22 as Viadana attacked. He quickly off-loaded to Tindall, who barged his way through the Italian back-line to make 30 metres.
Referee Rob Debney showed the yellow card to Viadana's Andrea Benatti for infringing and Mercier went to touch with his kick.
From the set-piece the pack was held up on the line, before Richards recycled to Henry Paul, whose looping pass put Morgan away for the try.
(22-0 to Glos)
Half time: Gloucester 22 Viadana 0
Samuel Pace, the Viadana right winger, took a quick tap penalty, and caught the Gloucester defence asleep from 30 metres out to score the visitor's first try.
Viadana's number eight Wannenburg broke from their 22, but Mercier stole the ball from him and threw an arching pass of 20 metres on the visitor's 22 to put Tindall away for his first Gloucester score. Mercier converted.
(29-5 to Glos)
Mark Cornwell was replaced by Alex Brown and was applauded from the pitch.
Boer scored his second try of the night when he powered through from half-way with great pace and power to the line. Mercier converted.
(36-5 to Glos)
Viadana's Joshua Sole gave Viadana the upper hand after the score with a darting run that evaded all of the Gloucester tacklers. Tindall was replaced by Anthony Allen and Balding came on for Narraway.
Jake Boer sealed his hat-trick after a breathtaking move that started on Gloucester's own line. Mercier did a 'show and go' and threw an inch perfect pass to Anthony Allen, who had replaced Tindall. The young centre found space through the Italian midfield on his own 22 and off-loaded to Henry Paul. Rob Thirlby injected more pace on the wing, before Boer took it on from 30 metres out for his third try. Mercier converted.
(43-5 to Glos)
Powell replaced Vickery.
Goodridge replaced Morgan at full-back.
As the crowd were occupied with a streaker, Gloucester's back-line went through a well rehearsed move on the Italian's 22 to put Jonny Goodridge through in the corner. Mercier converted from the touchline.
Mefin Davies replaced Jake Boer, who looked to come off as a precaution after a try-scoring match.
Gloucester broke from the their own line with a blistering move. Mercier dummied and off-loaded to Foster, who was held up on half-way. Mercier received treatment for a late tackle, whilst a Viadana player saw a yellow card for some off-the-ball incident.
McRae replaced Mercier, who was fine after the late tackle.
Thirlby added to the try tally with an individual effort that had the crowd on their feet. His electric pace saw the Italian defence simply stand still as he went for the corner.
(55-5 to Glos)
Thirlby's pace secured his second score of the match in the same corner as a few minutes earlier. Henry Paul's touchline conversion went straight through the sticks.
15. Olly Morgan (60 Goodridge), 14. Mark Foster, 13. Mike Tindall (53 Allen), 12. Henry Paul, 11. Rob Thirlby, 10. Ludovic Mercier (72 McRae), 9. Peter Richards, 1. Patrice Collazo, 2. Olivier Azam, 3. Phil Vickery (57 Powell), 4. Jonathan Pendlebury, 5. Mark Cornwell (51 Brown), 6. Jake Boer (M Davies 68), 7. Andy Hazell, 8. Luke Narraway (53 Balding).
Reps: 16. Terry Sigley, 17. Mefin Davies, 18. Gary Powell, 19. Alex Brown, 20. Adam Balding, 21. Haydn Thomas, 22. Duncan McRae, 23. Anthony Allen, 24. Jon Goodridge.