James Hook converted Shane Williams' injury-time try to give the Ospreys a dramatic Heineken Cup win over Sale.
Charlie Hodgson's second-half penalties had looked to been enough for Sale, but Hook held his nerve with the last kick of the match to grab the points.
The sides were level 10-10 at the break after a Williams"â¬â¢s try was cancelled out by Juan Fernandez Lobbe's score.
Hodgson's late penalty put Sale 10-16 up, but Williams found a way through the Sale defence for a thrilling end.
Ospreys suffered a late blow as Gavin Henson was forced to pull out of the starting XV with a hamstring injury.
Connor took over at fly-half and he helped the home side to an early advantage as the game began at an encouraging pace.
A second-minute penalty got the scoreboard ticking over and then Connor delivered the final pass that sent Williams over in the right corner for the opening try.
Scrum-half Justin Marshall created the damage with break inside his own half, and Williams showed great strength to withstand Hodgson's last-ditch tackle to touchdown.
Hodgson to charge down Byrnes kick, and the ball fell perfectly for number eight Fernandez Lobbe to gather and cross the tryline unopposed.
Hodgson converted, but then wasted the chance to put his side ahead by missing two penalties just before the half-hour mark.
Hodgson ended a poor first period with his first penalty to level the scores.
The England fly-half put Sale ahead for the first time in the match shortly after the break with his second penalty.
Hodgson stretched Sale's lead to six points with his third penalty three minutes from time and the victory looked safe for the Guinness Premiership champions
But the Ospreys suddenly came into life as the match entered injury time and camped themselves in the Sale 22. The Ospreys launched one final raid - a do-or-die extravaganza that spanned a nerve-jangling nine phases.
Their patience finally told as Byrne, after a superb hand-off on Oriol Ripol, fed Williams who brought the roller-coaster to a halt by rounding Sale's exhausted defence to score, and all eyes turned to look at Hook, but the youngster had eyes only for his target.
Ospreys coach Lyn Jones:
"I thought this game would go to the wire, and it is not nice to lose like that.
Ospreys: L Byrne; S Williams, S Parker, A Bishop, N Walker; S Connor, J Marshall; D Jones (capt), B Williams, A Jones, B Cockbain, I Evans, F Tiatia, S Tandy, R Jones.
Replacements: Hook for Connor (59), Spice for Marshall (67), James for D. Jones (67), Bennett for B. Williams (57), A. Jones for Cockbain (54), Thomas for Tiatia (57).
Sin Bin: Cockbain (38).
Sale: J Robinson (capt); M Cueto, M Taylor, E Seveali'i, O Ripol; C Hodgson, S Martens; A Sheridan, S Bruno, B Evans, C Jones, D Schofield, J White, M Lund, J Fernandez Lobbe.
Replacements: Larrechea for Cueto (12), Wigglesworth for Martens (45), Briggs for Bruno (66), Turner for Evans (45), Chabal for Schofield (55).
Not Used: Day, Mayor.
Referee: Joel Jutge (Fra).