"We managed to take him on loan for 18 months when normally you get somebody for six months or a year," he explained.
"I told him that if he scored 12 to 15 goals and if he looked sharp then he would have his deal. He's scored 11 but he's fulfilled his part of the bargain."
Jol introduced the striker as a substitute against West Brom on Monday night, and almost immediately his presence transformed the team's performance, producing a winning outcome along the way.
Jol added: "The first-half you can forget about but in the last 30 minutes we deserved to win."
Source: Daily Telegraph