|Connacht (3) 10|
|Cons: Carty Pens: Carty|
|Leinster (9) 9|
|Pens: Madigan 3|
Connacht stunned champions Leinster in Galway as they maintained their winning start to the Pro12 season and moved to the top of the table.
Ian Madigan kicked three penalties to help Leinster lead 9-0, but Jack Carty replied with three Connacht points before the interval.
Kieran Marmion's superb 55th-minute try was converted by Carty as Connacht moved into a one-point lead.
Despite late Leinster pressure, the home side held on to take a famous win.
The Sportsground erupted at the finish as Connacht ended an 11-match losing streak in Irish interprovincial derbies.
Marmion's early contender for try of the season saw the westerners make a bit of history by winning their opening three matches in the competition for the first time.
With Connacht falling foul of referee John Lacey in the early stages, Madigan slotted three wind-assisted penalties in the opening 16 minutes as Leinster threatened to put the match to bed early on.
But the home side began to find some midfield fluency as a couple of Matt Healy bursts helped set up a penalty which fly-half Carty slotted.
Captain John Muldoon's sin-binning for a side-entry at a ruck put Connacht on the back foot again but they had a reprieve when Leinster had a try ruled out after Jimmy Gopperth was correctly judged to have given a forward pass to the charging Madigan.
A Brendan Macken break set up another Leinster try-scoring chance before the interval but Connacht old boy Mike McCarthy was held up and a huge home shove then earned a relieving penalty from the resultant five-metre scrum.
Committed Connacht tackling continued to frustrate Leinster in the third quarter before Marmion's piece of individual brilliance helped the home side move ahead in the 55th minute.
The young Ireland scrum-half darted inside Madigan after a ruck near just outside the Leinster 10-metre line before gliding past Rob Kearney and replacement Cian Healy to score a glorious try.
Carty held his nerve in the windy conditions to slot the tricky conversion to put Connacht into the lead.
A couple of huge hits by Dave McSharry on Kearney prevented Leinster from producing a quick response as the champions were forced to bring on big guns such as Gordon D'Arcy.
Leinster did produce intense pressure at the death but could not engineer a drop goal chance for Gopperth as Connacht kept their nerve and discipline to record a win greeted rapturously by the home crowd.
Connacht: Leader; Adeolokun, Henshaw, McSharry, Healy; Carty, Marmion; Buckley, Heffernan, White; Muldowney, Roux; Muldoon, Faloon, McKeon.
Replacements: Ronaldson for Leader 69, Carr for Adeolokun 41, Porter for Marmion 69, Loughney for Buckley 80, Ah You for White 66, Kearney for Roux 50, Naoupu for Faloon 33
Not Used: Delahunt.
Leinster: R Kearney; McFadden, Macken, Madigan, Fanning; Gopperth, Boss; J McGrath, Cronin, Ross; Toner, M. McCarthy; Ruddock, Ryan, Heaslip, Jennings.
Replacements: D'Arcy for Macken 58 mins, Healy for J McGrath 46, Reddan for Boss 60, Furlong for Ross 66, Jennings for Ruddock 61, M McGrath for Jennings 72, .
Not Used: B Byrne, Denton
Referee: John Lacey (IRFU)