NEWCASTLE, England (AP) — Premier League leader Chelsea slipped to its first defeat of the season by losing 2-1 at Newcastle on Saturday, with substitute Papiss Cisse scoring both of the home side’s goals in the second half. Cisse scored in the 57th and 78th minutes before Newcastle had defender Steven Taylor sent off in the 81st for a second yellow card. Substitute Didier Drogba reduced the deficit two minutes later by heading in Cesc Fabregas’ free kick but relentless pressure from Chelsea failed to deliver an equalizer. The loss ended Chelsea’s 23-match unbeaten run in all competitions stretching back to April. Jose Mourinho’s team hadn’t lost in 21 games this season. Second-place Manchester City could reduce the gap to Chelsea to three points by beating Everton later Saturday. Chelsea was looking to set a new club record of 24 matches unbeaten by avoiding defeat at Newcastle but was sunk at a ground where it has now lost in three straight seasons. Mourinho hasn’t won in five trips to St. James’ Park. In a dramatic finish, Newcastle had 21-year-old goalkeeper Jak Alnwick — who came on as a halftime substitute for his competitive debut following an injury to Rob Elliot…