Melbourne Victory coach Jim Magilton has put himself on a collision course with Matthew Kemp, refusing to guarantee the defender another game at the club.The eighth-placed Victory's A-League finals hopes took a battering on Saturday night when they lost at home for the first time this season, going down 3-1 to the sixth-placed Newcastle Jets.Ryan Griffiths opened the scoring for the Jets in the 20th minute and 19-year-old Jacob Pepper bagged a double after Victory star Harry Kewell had slotted a penalty in the 24th minute.Kewell also missed a penalty late in the first half and Archie Thompson hit the crossbar.Tensions within the Victory camp were on show when Kemp was subbed off in the 42nd minute following a series of defensive lapses.Kemp was furious, waving his hand dismissively as he stormed off down the tunnel.Magilton described Kemp's reaction when subbed off as "totally unacceptable".Asked if it was Kemp's last game for the club, Magilton said: "Who knows?"Magilton said he couldn't fault the effort of his players although they conceded three poor goals."Defensive frailties have probably cost us all season," Magilton said."If it comes down to a lack of quality, or poor decision-making, there isn't an awful lot you can do."Midfielder Carlos Hernandez was red-carded late in the match after being awarded his second yellow.The former A-League player of the year initially refused to leave the field and argued with the Newcastle bench as he walked off."Should he have shown restraint? Yes. (But) I didn't think it was a booking," Magilton said."He clearly got the ball."Seventh-placed Sydney FC host the Victory on Saturday night in the third-last round of the season.Magilton and Kewell insist the Victory's finals hopes are still alive."We let in three sloppy goals ... it's heartbreaking," Kewell said."We've still got a chance. We're going to go up to Sydney next week and put on a good show."Newcastle coach Gary van Egmond said the Victory were no longer intimidating sides and their confidence was down despite having big names such as Kewell, Thompson and Hernandez."The confidence levels, a little bit of doubt, that also gives the opposition teams more confidence and less doubt for themselves," the Jets coach said.Van Egmond said his side produced some magnificent goals in the first half against the Victory.The Jets have won five of their past six games but the man who led them to the title four seasons ago says it's too early to talk up his team's finals prospects."We've got Gold Coast next week. They're a very unpredictable team with a lot of things that are going on right at this moment," van Egmond said.The Jets host the troubled Gold Coast on Friday.