Lionel Beauxis kicked 17 points for Toulouse as they comfortably beat Connacht, who were playing their first-ever Heineken Cup home match.
Beauxis's accurate kicking and Jean Bouilhou's try ensured Toulouse quietened the home fans and raced into a 22-3 lead at the break.
A controversially awarded penalty try put the result beyond any doubt.
Connacht gained a penalty try themselves, but Yannick Nyanga barged through for the visitors' third.
A record crowd of 9,120 had turned up to watch Eric Elwood's men take on the four-time European champions in this Pool Six encounter.
Connacht hardly made a mistake in the opening quarter, their captain Gavin Duffy leading by example, but Toulouse's quality was glaringly obvious.
Beauxis kicked the visitors 9-0 ahead then worse followed for the Irish province in the 22nd minute. Louis Picamoles and Thierry Dusautoir both carried forward before Bouilhou squeezed over.
Connacht's Mike McCarthy then caught the onrushing Vincent Clerc with a neck-high challenge and was promptly sin-binned.
Miah Nikora slotted a penalty from in front of the posts to get Connacht off the mark, before Toulouse's dominant scrum yielded three more points for Beauxis.
Seven minutes into the second half, referee Greg Garner earned the ire of the home fans when he awarded Toulouse a penalty try after just one wheeled scrum.
The French side had the platform of a five-metre scrum and as it spun around the English official gave the verdict to the visitors, with Beauxis adding the extras.
Ethienne Reynecke saw yellow for taking Luke McAlister out as he chased his own kick, and Nyanga went on a bulldozing run to touch down with three minutes left.
Connacht: Duffy; O'Halloran, Griffin, McSharry, Tuohy; Nikora, O'Donohoe; Wilkinson, Flavin, Ah You; Swift, Gannon; McCarthy, Muldoon, Naoupu.
Replacements: Fa'afili for Griffin (71), F Murphy for O'Donohoe (52), Loughney for Wilkinson (64), Reynecke for Flavin (49), Rogers for Ah You (49), Anderson for Muldoon (64).
Not used: Ofisa, N. O'Connor.
Sin Bin: McCarthy (29), Reynecke (75).
Toulouse: Poitrenaud; Medard, Fritz, Jauzion, Clerc; Beauxis, Burgess; Montes, Servat, Johnston; Lamboley, Maestri; Bouilhou, Dusautoir, Picamoles.
Replacements: McAllister for Poitrenaud (50), Vergallo for Burgess (61), Poux for Montes (69), Botha for Servat (50), Falefa for Johnston (53), Millo-Chluski for Maestri (54), Galan for Picamoles (60), Nyanga for Millo-Chluski (68).
Referee: G Garner.