Sam Allardyce believes West Brom have given themselves hope of pulling off an incredible escape after “demolishing” Chelsea at Stamford Bridge. West Brom rose to seven points behind 17th-placed Newcastle after ending Thomas Tuchel’s unbeaten start at Chelsea, who were a shambles after losing Thiago Silva to a red card in the first half. Matheus Pereira and Callum Robinson were inspired for the visitors and Allardyce believes his side can stay in the Premier League if they win five of their last eight games. “It gives us hope,” West Brom’s manager said. “Perhaps on the quality of the performance and the way we demolished Chelsea, a little bit more than hope. Can we reach this level against Southampton on Monday week? It keeps us alive. “They demolished a Chelsea with an undefeated record since the new manager arrived. That’s what the Premier League is about – teams at the bottom beating teams at the top. People cannot say Chelsea were under par. They were off form because we were so good. We need five wins out of the last eight to give ourselves a chance. Still that might not be enough. Let’s start against Southampton.” Pereira and Robinson both scored twice, with Mbaye Diagne also getting himself on the scoresheet. Chelsea, who had not lost in 14 games under Tuchel, were awful. They struggled before losing Silva to a second booking and face a fight to hold on to fourth place. Tuchel, who must rouse his side before the first leg of their Champions League quarter-final against Porto on Wednesday, hopes his first defeat serves as a wake-up call. “I trusted this lineup,” Chelsea’s manager said. “We were sloppy in the buildup. We made many unforced errors. We gave away easy ball losses that lead to a red card. It cost us the game. “We were not able to adapt to one man down. There was absolutely no reason to concede five goals. It is my responsibility. There is no other option but to accept it. In four weeks hopefully we look at it as a wake-up call.” Chelsea, who lost Silva moments after Christian Pulisic had put them 1-0 up, had conceded only two goals under Tuchel before facing West Brom. “To give a red card away straight after the goal, we did not feel the risk,” Tuchel said. “The attitude in the defending was not the same as before.”