Michalak kicked a drop-goal and two penalties that underlined early Toulouse dominance, while Skrela converted Medard's fourth-minute touchdown, yet the Dragons gave it their best shot.
But Michalak missed a drop-goal from almost in front soon after his introduction, while Wilkinson hit the upright with a right-foot effort in the 59th minute.
France number 10 Michalak missed a penalty from halfway in the 36th minute, and moments later O'Gara was successful with a 25-metre drop-goal to reduce the arrears to 9-3.