Debutant flanker Jerry Collins scored the game's only try and Dan Biggar and James Hook kicked the rest of the points as the Ospreys secured a deserved win over Connacht.

Michael Bradley's charges endured a second half collapse at the Sportsground, losing new number 8 Mike McComish and scrum half Frank Murphy to the sin-bin in quick succession.

Taking full advantage, the Ospreys scored ten crucial points during that spell with Biggar booting a penalty and converting Collins' score which came after a surging forward drive.

But Connacht, restored to 15 players, showed their battling qualities as they fought back to claim a late bonus point thanks to Ian Keatley's fourth successful penalty.

The westerners, who finished bottom of the table last season, included three of their new signings from the kick-off - Ireland Sevens internationals McComish and Brian Tuohy and New Zealander Bernie Upton, the former Chiefs and Hurricanes lock.

All Black powerhouse Collins and former Scarlets full-back Barry Davies made their competitive bows for the Ospreys, with coach Sean Holley also handing scrum half Mike Phillips an immediate return after his exploits with the Lions.

A late switch saw Jonathan Spratt drafted in as a last-minute replacement for injured centre Andrew Bishop (shoulder).

Connacht had the backing of the wind in the first half but after an early Keith Matthews break was snuffed out, the Ospreys began to shade it in the possession stakes.

In a stop-start first quarter, teenage fly-half Biggar kicked the visitors ahead with a snap drop goal in the ninth minute.

Phillips busily plugged away behind the Ospreys pack, however Connacht hit back midway through the half when a push in the lineout allowed Keatley land his first penalty success.

Recent Ireland cap Keatley attacked off the restart, making a surging 28-metre break. He found Niva Ta'auso up in support and while the move petered out, the Ospreys leaked another penalty which Keatley converted for a 6-3 interval lead.

Connacht had two attacking lineouts in the Ospreys 22 but poor execution let them down and they failed to press their advantage when the Ospreys lost lock Andy Lloyd to the sin-bin, five minutes before the break.

Biggar kicked his side level at 6-6, four minutes into the second half, and the Welsh outfit turned the screw, dominating possession through their pack and looking more dangerous out wide as the third quarter wore on.

Keatley hit the post with a penalty chance and Biggar edged the visitors ahead with his second penalty and when a controversial decision against Murphy, who was adjudged to have deliberately slapped the ball out of Phillips' hands, put Connacht down to 13 players - the breakthrough try duly arrived.

Ian Gough won possession off a 60th-minute lineout close to the Connacht line and a powerful drive saw Collins crash over the line. Biggar kicked the conversion for some extra cushion at 16-6.

The Ospreys had chances to build on their lead but a lone penalty from replacement James Hook was all they could muster in the final quarter.

To their credit, Connacht clawed their way back into the game and two more Keatley kicks earned them a point for a typically committed showing.

Speaking after the game, Ospreys coach Sean Holley said: "It was a very difficult game against tough opponents in testing conditions, and I've got mixed emotions after the final whistle.

"Obviously, I'm delighted that we've got off to a winning start, but there's disappointment at the performance if I'm honest.

"There was a very strong wind which made life difficult for us in the first half, but I felt that we used it well after the break when we had a lot of pressure.

"There were some pleasing individual performances out there, Dan Biggar coped well with the wind and scored a good drop goal to put us ahead after some early pressure and in the second half, his kicking was excellent.

"He made sure Connacht paid for another penalty offence with a good kick to the corner that we then drove over and an excellent penalty from out wide took us clear.

"I thought Jonathan Spratt worked hard and looked dangerous and Jerry Collins gave us some excellent 'go forward' against a stubborn defence.

"Some indiscretion at the end allowed Connacht to get the bonus point that their efforts probably deserved, but I thought that there was only going to be one winner in that second half."