Nottingham Forest's Brennan Johnson scored the winner but it was debutant keeper Keylor Navas they had to thank for a gritty 1-0 Premier League home victory over Leeds United on Sunday. The 36-year-old Costa Rican, signed on loan from Paris St Germain until the end of the season, pulled off a string of superb reflex saves to deny a Leeds side who dominated possession, but could not find a way past him. Forest took the lead against the run of play when Leeds defender Pascal Struijk fouled Johnson and he compounded the error by botching his headed clearance from the free kick, teeing up a chance for Johnson. The Welsh forward needed no further invitation, firing a rasping volley into the net to breaking the deadlock with his side's first effort on target. The visitors could have levelled but Luis Sinisterra somehow blasted his effort high over the bar with the goal at his mercy, and when Leeds managed to get efforts on target Navas reacted smartly to keep them out. Despite spending much of a frenetic second half defending, Forest held on to extend their unbeaten run in the Premier League to five games. They moved up to 13th in the table on 24 points, six ahead of Leeds who are 17th.