Connacht continued their winning start to the season with another tight triumph, this time a 14-13 victory over Edinburgh Rugby thanks to Willy Faloon's last-gasp try.
Tom Heathcote's boot and a try from Cornell du Preez gave Edinburgh a 13-6 lead at half time; Connacht's points coming from two Darragh Leader penalties.
Faloon was sent to the sin bin with 16 minutes left on the clock, but returned to touch down the winning try in the dying minutes.
Ospreys remain top of the tree by one point after winning 17-15 at the Newport Gwent Dragons.
Dan Bigger marked his 150th Ospreys appearance with seven points from the tee, converting both Rhys Webb and Eli Walker's tries.
The Dragons' points were all from penalties, four from Angus O'Brien and one from Jason Tovey.
Glasgow also remain unbeaten, this time with a more convincing 33-12 win over Cardiff Blues.
The game was tightly contested until the final 20 minutes, when replacement Niko Matawalu scored two quick and impressive tries, adding to Sean Lamont's first-half score.
Rhys Patchell scored all of the Blues points including a penalty from inside his own half - a feat he also achieved last weekend.
Five tries from Ulster were more than enough to see them past Zebre at the Kingspan Stadium, including one from man-of-the-match Andrew Trimble.
Dan Tuohy, Robbie Diack, Nick Williams and Craig Gilroy also touched down for the Ulstermen, with Samuela Vunisa getting one for the Italians.
Munster got back to winning ways after their round one blip, downing Benetton Treviso 21-10 thanks to 11 points from Ian Keatley.
CJ Stander and Simon Zebo were Munster's try scorers, responding to Simone Ragusi's early score.
And Leinster secured their second bonus point of the season, running in six tries against the Scarlets, with Rob Kearney and Ian Madigan scoring twice.
Dominic Ryan and Tadhg Furlong added two more, with Joe Snyman and Scott Williams crossing the whitewash for the Welsh side.
TRY OF THE WEEKEND
Willie Faloon's winning try for Connacht at Murrayfield was certainly one for the purists, but Pat Lam's side will take all the wins they can.
A textbook five-metre lineout saw the ball end up in Faloon's hands at the back of the rolling maul.
And the former Ulster player added his power to the pack, driving Edinburgh backwards and eventually touching down.
BREAK OF THE WEEKEND
Sean Lamont's first-half score for Glasgow came out of nowhere, but the Scotland international still had to use a bit of skill to find the try line.
Lamont helped Chris Fusaro prise the ball from Cory Allen's grasp on half-way before the hulking winger powered down the left wing.
A dummy side-step was enough to send Rhys Patchell sprawling, allowing Lamont to continue to the corner untouched.
PLAY OF THE WEEKEND
Rob Kearney's second try of the day against the Scarlets was started and finished by himself, although somewhat fortuitously.
Close to the right touchline, the full-back chipped the ball inside for one of his Leinster teammates to run on to.
But the bouncing ball evaded everyone except Kearney who powered through to touch down.
PLAYER OF THE WEEKEND
All of the Leinster backs could be in line for this accolade, but Ian Madigan certainly took the game to the Scarlets, scoring two tries and knocking over all six conversions for his side.
The centre's trickery and pace was key to his two trips across the whitewash, proving a constant nuisance to the Welsh side's defence.
Follow us on Facebook, join the conversation on Twitter, sign up to our YouTube channel for extensive match highlights and sign up for our newsletter for regular updates on the GUINNESS PRO12
Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland