Motherwell can count themselves lucky to have escaped with such a narrow defeat in France, having been largely outplayed for much of the night and seeing a second-half penalty saved by their goalkeeper Graeme Smith.
The Scots found themselves under pressure from the off and Mark Reynolds was fortunate to escape punishment for catching Helder with a high boot as the Brazilian was about to burst into the box. Motherwell, playing a 4-5-1 formation with David Clarkson wide right, were struggling to mount attacks and Nancy posed questions from set-pieces. The visitors gave the ball away too cheaply and were grateful for Stephen Craigan's intervention as Mosef Zerka headed towards goal from 10 yards.
John Sutton cut an isolated figure up front as every long ball came straight back into the Motherwell half. They seemed to be weathering the storm but Nancy's possession eventually told in the 42nd minute. Jean Calve whipped in a cross from the right and Pascal Berenguer got in front of Keith Lasley to head into the far corner from the edge of the area. Smith comfortably held Zerka's ambitious attempted chip moments later.
Motherwell did break in the 61st minute and Clarkson had a penalty appeal rejected when Nancy substitute Issiar Dia appeared to brush his legs as he cut inside following Marc Fitzpatrick's ball. The French should have wrapped things up when Reynolds brought down Julien Feret in the area but Smith saved Dia's spot-kick.
AS Nancy: Bracigliano; Helder (Dia 56), Macaluso, Chretien, Ouaddou, Calve, Malonga Ntsayi (Fortune 56), Berenguer, Brison, Feret (N'Guemo 87), Zerka. Substitutes not used: Gregorini, Sami, Andre Luiz, Biancalani.
Motherwell: G Smith; Quinn, Craigan, Reynolds, Hammell, Malcolm (Smith 67), Lasley, Fitzpatrick, Hughes, Clarkson (Murphy 82), Sutton (Porter 67). Substitutes not used: Nielsen, Darren, O'Brien, McGarry, Connolly.
Referee: V Hrinak (Slovakia).