Record signing Alexander Isak headed Newcastle back into the Premier League's top three after old boy Aleksandar Mitrovic had fluffed his lines for Fulham.The £60million striker's third goal for the club secured a hard-fought 1-0 victory at St James' Park, but only after one-time Tyneside favourite Mitrovic had seen a successful penalty ruled out for a double contact.Eddie Howe's men, who controversially included Joelinton in their starting line-up despite his midweek arrest for drink-driving, leapfrogged Manchester United back into third place in the table as a result of extending their unbeaten league run to 14 games.Fulham, however, may feel hard done by after frustrating their hosts for long periods and threatening repeatedly on the counter.FULL MATCH DETAILSJoe Willock curled a third-minute attempt wide after cutting inside from Joelinton's flick-on and Issa Diop got in an important block to deny Sean Longstaff after he had run on to Bruno Guimaraes' clever reverse pass two minutes later.Mitrovic was similarly snuffed out at the other end as the visitors responded, but full-back Kenny Tete might have done better with his follow-up from the edge of the box, which he skied high over.Fulham were working their way into the game with Andreas Pereira and Willian starting to make an impression behind Mitrovic, although Callum Wilson saw a 21st-minute effort deflected across goal after Miguel Almiron had played Sean Longstaff in behind full-back Layvin Kurzawa.Wilson powered a header into keeper Bernd Leno's arms from Kieran Trippier's cross as Newcastle stepped up a gear, and the striker was unable to make meaningful contact with Willock's cross after the midfielder's fine first touch had taken him past Tete 12 minutes