The Scottish capital side have now pulled four points clear of early leaders Newport Gwent Dragons, who are tied on nine points with European champions Leinster.
The Magners League's reputation for tight games was confirmed with one of the closest rounds yet, four out of the five losing teams claiming a losing bonus point.
Only a resurgent Dragons were able to pull more than seven points clear of their opponents, Glasgow Warriors.
The league's top try scorer, Fionn Carr, has scored all three of Connacht's tries so far this season, while two Scottish players, Chris Paterson and Dan Parks, are currently the league's top point scorers.
Edinburgh's win at Ulster was their ninth consecutive Magners League victory.
Meanwhile, at the opposite end of table, Cardiff have yet to record their first win of the season having lost to Connacht at the Sportsground on Friday night.
2009/10 MAGNERS LEAGUE - AFTER ROUND 3:
TOP TRY SCORERS -
3 - Fionn Carr (Connacht)
2 - Aled Brew (Newport Gwent Dragons), Ashley Smith (Newport Gwent Dragons), Jerry Collins (Ospreys), Simon Danielli (Ulster), Denis Hurley (Munster), Alan MacDonald (Edinburgh), Mark Robertson (Edinburgh), Chris Paterson (Edinburgh), Tim Visser (Edinburgh)
TOP POINTS SCORERS -
47 - Chris Paterson (Edinburgh) (2 tries, 11 conversions and 5 penalty goals)
43 - Dan Parks (Glasgow Warriors) (2 conversions, 12 penalty goals and 1 drop goal)
38 - Jonathan Sexton (Leinster) (1 conversion and 12 penalty goals)
35 - Ben Blair (Cardiff Blues) (1 try, 3 conversions and 8 penalty goals)
30 - Jeremy Manning (Munster) (3 conversions and 8 penalty goals)
26 - Ian Keatley (Connacht) (1 conversion and 8 penalty goals)
24 - James Arlidge (Newport Gwent Dragons) (1 try, 2 conversions, 4 penalty goals and 1 drop goal)
21 - Rhys Priestland (Scarlets) (3 conversions and 5 penalty goals)
BEST PLACE-KICKERS -
100% - Daniel Evans (Scarlets) (1 successful kick from 1 attempt)
88.89% - Chris Paterson (Edinburgh) (16/18)
84.62% - Ben Blair (Cardiff Blues) (11/13)
81.25% - Jonathan Sexton (Leinster) (13/16)
75% - Jason Tovey (Newport Gwent Dragons) (3/4)
73.68% - Dan Parks (Glasgow Warriors) (14/19)
64.29% - Ian Keatley (Connacht) (9/14)
61.11% - Jeremy Manning (Munster) (11/18)
60% - Dan Biggar (Ospreys) (3/5)
53.33% - Rhys Priestland (Scarlets) (8/15)
RESULTS ROUND-UP -
Friday, September 18, 2009 at the Sportsground
Connacht (3) 18: Fionn Carr(2T), Ian Keatley(C/2P)
Cardiff Blues (10) 16: Ben Blair(T/C/3P)
Connacht v Cardiff Blues Match Report
Friday, September 18, 2009 at Ravenhill
Ulster (13) 13: Stephen Ferris(T), Ian Humphreys(P), Clinton Schifcofske(T)
Edinburgh Rugby (7) 16: Phil Godman(D), Chris Paterson(C/2P), Tim Visser(T)
Ulster v Edinburgh Match Report
Friday, September 18, 2009 at Liberty Stadium
Ospreys (8) 11: James Hook(2P), Jerry Collins(T)
Leinster (6) 18: Jonathan Sexton(5P), Isa Nacewa(D)
Ospreys v Leinster Match Report
Friday, September 18, 2009 at Rodney Parade
Newport Gwent Dragons (22) 30: Jason Tovey(T/2P), Aled Brew(T), James Arlidge(T/2C), Ashley Smith(T)
Glasgow Warriors (16) 19: Dan Parks(C/4P), Colin Shaw(T)
Saturday, September 19, 2009 at Parc y Scarlets
Scarlets (10) 20: Mark Jones(T), Deacon Manu(T), Rhys Priestland(2C/P), Daniel Evans(P)
Munster (10) 22: Denis Hurley(2T), Jeremy Manning(2C/P), Toby Morland(T)