The 34-year-old keeper had his net breached on three occasions for the first time this season in a 3-0 defeat to Derby in midweek, as the Magpies surrendered top spot in the Coca-Cola Championship to West Brom.

It was only the fourth league defeat of the season for the St James' Park outfit and their first since a 2-1 reverse at Scunthorpe in October.

"We were on a very good unbeaten run but that doesn't just carry on because you're up there at the top - you have to earn it and work for it," Harper told www.nufc.com.

"Luckily we have another game now just around the corner against Swansea, and it goes without saying that we're demanding a response from everyone.

"One defeat is not going to stop us; we showed that following the game at Scunthorpe when we were beaten earlier in the season. We were united after that and have been since.

"Swansea is a tough place to go but we have to rise to the challenge and come away with a positive result."

The Swans moved up to fifth in the table with a 1-0 win at Crystal Palace on Tuesday night, ending a 90-year winless run at Selhurst Park and extending their unbeaten league sequence to eight matches.

Another of the Magpies' promotion rivals, Nottingham Forest, travel to the Keepmoat Stadium to face Doncaster.

Forest lasted until January without a league defeat on their travels this season, before losing 1-0 in successive away matches to Derby and Coventry.

Ending that run will be the priority for Billy Davies' men against Rovers, as attempt to keep pace with the automatic promotion places.

Saturday's fixtures also see Barnsley hoping to give their play-off aspirations a boost against struggling Plymouth, yet manager Mark Robins has exercised concern ahead of the Pilgrims' visit.

"It will be a tough test for us on Saturday and Plymouth will be fighting for their lives," explained Robins to www.barnsleyfc.co.uk.

"Plymouth play a certain way and we will have to cope with that and earn the right to play our football.

"They will work hard as a team and make it difficult for us. They come here (Oakwell) for anything they can get and will fight for everything."

Elsewhere, fellow top-six candidates Leicester and Sheffield United host Scunthorpe and Bristol City respectively, and bottom club Peterborough go in search of their first away win of the league campaign as they play Middlesbrough.