Brechin City manager Dick Campbell is close to agreeing a deal to take charge at Firhill, so Lambie must have been disappointed to sign off by seeing his side squander a half-time lead.
The Jags went ahead four minutes before the break, but the goal had more than a hint of offside about it.
Armand One appeared to be well offside but the referee ignored the fact that he dummied Andy Gibson's pass on its way to Derek Fleming.
Fleming then advanced to the edge of the box and fired beyond Craig Hinchcliffe.
However, Partick could not hold on to the lead and the Buddies were level just six minutes after the interval, when Jean-Yves Anis put through his own goal under pressure from Kirk Broadfoot.
Both sides looked for a winner in the closing stages but heavy rain made passing football almost impossible and neither side could create a telling opportunity to clinch the points.