Lions duo Alex Corbisiero and George North made their debuts for Northampton Saints in a 24-8 victory over Edinburgh, Phil Dowson scoring two tries in the second-half to secure the win.
A repeat of last year's RaboDirect Pro12 Final saw Ulster pip Leinster 21-19, replacement Ian Porter crossing for the winning try at a renovated Ravenhill.
Newport Gwent Dragons produced an encouraging 22-20 victory over Bath at The Rec, the boots of new signings Kristopher Burton and Jason Tovey doing the damage in the second half.
Munster did enough to overcome a tricky Gloucester outfit in the wet at Thomond Park, running in four tries to win 28-17 with JJ Hanrahan coming on to notch up the fourth score and add two conversions. Former All Black Jimmy Cowan was also a try-scorer for Gloucester, as he continues his comeback from a serious knee injury.
Only a late try from Matt Hopper ensured victory for Harlequins over Glasgow Warriors at the Stoop, a near full-strength outfit for the 2012 Aviva Premiership champions squeezing home 19-16.
There were no such problems for Leicester Tigers, who ran in 11 tries against Championship side Jersey for a 69-7 win - new signing Ryan Lamb grabbing a brace.
Saracens produced a similar outcome against Cornish Pirates, running up a final score of 61-3 as James Johnston and Billy Vunipola made their debuts.
Exeter Chiefs scored eight tries in a simple hitout against former Championships rivals Bristol, winning 51-7 as young fly-half Henry Slade scored a double and kicked four conversions.
London Wasps sealed a pre-season 30-12 derby victory over London Irish, outscoring the visitors three tries to two in their final pre-season match.
Premiership new boys Newcastle Falcons downed Connacht thanks to tries from Ryan Shortland and Andrew Higgins, whilst Cardiff Blues were comfortable winners over Sale Sharks as they played on the new artificial surface at Arms Park to win 45-24.
A youthful Scarlets side were held to a 16-16 draw with London Welsh, but no one's pre-season fixture was more eventful than Worcester's.
After their team bus spectacularly caught fire en route to play the Ospreys, with fortunately nobody hurt, Dean Ryan's side were denied victory after a late try from Ross Jones gave the hosts a 23-19 victory.