Oxford are still looking for their first point of the new season after a Billy Kee double earned Accrington a 3-2 win at the Kassam Stadium.
Stanley twice fought back from going a goal behind before Kee fired home a late penalty - his second goal of the game.
Gavin Whyte put Oxford in front with a stunning strike after 27 minutes, hammering a right-footed drive high into the net from 18 yards, before he smashed a left-footed 20-yard drive against the post.
But Accrington levelled two minutes before half-time when Sean McConville's free-kick was turned into his own net by Cameron Norman.
Oxford regained the lead in the 57th minute with a superb solo goal from Marcus Browne, cutting in from the left to shoot home. Yet Kee levelled again five minutes later, lashing the ball home when John Mousinho missed a cross.
And the striker completed Oxford's misery by rifling a spot-kick into the bottom right corner 11 minutes from time after Josh Ruffels tripped Jordan Clark.