Dragons: (6) 13
The Dragons cover arrived too late to stop Lloyd from scoring
Con: A. Thomas
Pens: A.Thomas (2)
Ospreys: (10) 27
Tries: Lloyd, S. Williams (2), Tiatia
Cons: Hook (2)
The Ospreys moved to within a point of Magners League leaders Leinster with a bonus-point victory over the Dragons.
Andy Lloyd and Shane Williams crossed for unconverted first-half tries, but the home side stayed in touch with two Aled Thomas penalties.
Williams and Filo Tiatia scored twice in as many minutes soon after the break, with James Hook converting both.
Shaun Connor added a penalty on 79 minutes, before Gareth Maule's try was just reward for the Dragons' endeavour.
Leinster will win the title on Friday night at the Arms Park by beating Cardiff Blues with a bonus point in their final game of the season.
But anything less than five points means the Ospreys can snatch the crown with a bonus-point win at the Borders on Saturday night.
The Ospreys were far from their best in an error-strewn game, but they still managed to claim their first league win at Rodney Parade without needing to hit the top gears.
The Dragons, fielding seven academy players because of a lengthy injury list, were on the back foot immediately after Thomas had given them a seventh-minute lead from a penalty.
Ospreys flanker Richie Pugh came within inches of opening his side's try count when he was held up over the tryline, but the opening score came from the resulting five-metre scrum on 14 minutes.
Flanker Jon Thomas picked up at the base and quickly fed Lloyd, who was as surprised as anyone to find a clear passage to the line ahead of him.
Hook, playing at inside centre, hooked the relatively simple conversion attempt wide.
The second try was all down to the classy Ospreys backs as they swept the ball quickly across the pitch inside the Dragons' 22.
Full-back Lee Byrne delivered the decisive pass with superb slight of hand under pressure to allow winger Williams to dive over in the right corner.
Hook made far better contact with his second conversion, but the stiff breeze meant the ball fell just short.
Having just missed one long-range penalty, Thomas quickly made amends to cut the deficit to just four points at the break.
One of the Rodney Parade floodlights failed early in the second half, but Williams soon illuminated proceedings with an outrageous finish.
The Dragons defenders seemed to switch off as Williams' chip-kick headed for touch, but Williams reacted with in a flash as the ball checked and he touched down with only a few inches to spare.
Another mistake from the home side allowed the Ospreys to secure the precious bonus point two minutes later.
A lineout throw five metres out flew over the intended recipient, allowing Tiatia to gather and run through a gaping hole to score.
Hook converted both scores and the tension seemed to lift off the Ospreys' shoulders.
The Dragons still looked dangerous, though, and only superb covering work from Ospreys scrum-half Jason Spice denied his opposite number Gareth Baber a solo score just before the hour.
But the home side finally broke through five minutes into injury time when centre Maule scored under the posts after a period of sustained pressure.
Dragons: M. Thomas; Wyatt, Maule, P. Dolman, Norris; A. Thomas, Walker; Maddocks, Daly, Corsi, Hall, Sidoli, Lydiatt, Bearman, Owen (capt).
Replacements: Emerick for P. Dolman (80), S. Thomas for Norris (67), Jones for Daly (53), Robinson for Corsi (53).
Not Used: Gough, Ringer, Cooper.
Ospreys: Byrne; Vaughton, Parker, Hook, S. Williams; Connor, Spice; James (capt), B. Williams, Millward, Powell, A. Jones, Thomas, Pugh, Lloyd.
Replacements: Selley for Vaughton (65), A. Bishop for Hook (73), Roberts for Spice (74), Hibbard for B. Williams (65), D. Jones for Millward (23), Beech for Powell (74), Tiatia for Lloyd (36).
Referee: Nigel Owens (WRFU)