Glasgow slipped to second-bottom in the Magners League after they were narrowly beaten by Treviso in Italy.
A low scoring first-period ended 6-6, with Glasgow stand-off Ruaridh Jackson and Willem de Waal of Treviso both slotting over two penalties.
Home flanker Robert Barbieri and Glasgow centre Graeme Morrison traded converted tries after the break.
Jackson and De Waal each scored another penalty, before De Waal's drop-goal clinched victory for the hosts.
Despite kicking 11 of Glasgow's points, it was two penalty misses by Jackson which ulitmately proved crucial, and Treviso overtake the Scots at the lower end of the league table.
It took nine minutes for Treviso to put the first points on the board as De Waal landed a penalty from long range.
Jackson responded on the quarter-hourand then kicked the next points in the 27th minute, before the hosts levelled on the stroke of half-time.
A fiery start to the second period saw a stamp by Ryan Grant spark a minor fracas, and the Glasgow prop was yellow-carded for his part in the incident.
Treviso scored their only try while their opponents were down to 14 men, De Waal receiving good ball from a lineout and feeding Barbieri, who burst through a gap and beat two tacklers before stretching over the whitewash.
Jackson missed a chance to cut the deficit with a penalty but, with Grant still off the field, Glasgow captain Morrison found a gap in the Italian defence and crossed for the match-levelling try.
The return of Grant did little help to Glasgow as De Waal put his side ahead once again after an infringement in the Scottish scrum, but Jackson was quick to respond once again, slotting over in the 55th minute to make it 16-16.
However, De Waal landed the match-winning points from open play after being teed up 40 yards out.
Jackson howled in anguish after another costly miss and the Warriors were unable to find a way through in several phases of attacking possession late on.
Treviso: Williams, Sepe, Sgarbi, Garcia, Nitoglia, De Waal, Semenzato, Muccignat, Ghiraldini, Rouyet, A. Pavanello, van Zyl, Barbieri, Zanni, Derbyshire.Replacements: Vidal, Rizzo, Cittadini, Bernabo, Vosawai, F. Minto, Picone, McLean.
Glasgow: Murchie, O'Hare, Aramburu, Morrison, Van der Merwe, Jackson, Cusiter, Grant, Hall, Low, Muldowney, Ryder, Harley, Vernon, Beattie.Replacements: Thomson, Tkachuk, Welsh, Fusaro, Wilson, Gregor, Weir, Horne.
Referee: Dudley Phillips