Costa glided by Jonny Evans but shot wide and Willian fired off target either side of McClean heading off target from Darren Fletcher's cross.James Morrison departed with an apparent hamstring problem before Azpilicueta blocked a Fletcher effort and then scored at the other end.Azpilicueta is less than prolific, but likes scoring against West Brom.The full-back, who netted at The Hawthorns in August, claimed his first goal at Stamford Bridge when he prodded in Branislav Ivanovic's cross at the back post.There were holes aplenty in the visiting defence, but Chelsea's rearguard was porous too.The Baggies breached and exposed when Pedro gave the ball away to Fletcher, who was influential for the visitors.Fletcher prodded it to Gardner, who did the rest, shooting into the bottom corner from 25 yards.Costa ballooned an effort over and Salomon Rondon shot just wide as both sides had chances to take an interval lead.Pedro made his debut at The Hawthorns and inspired Chelsea to a first win of the season, but his star has faded since.The subdued Spain winger was withdrawn for Kenedy at half-time and the Brazilian gave Chelsea much-needed pace and penetration in an increasingly disjointed contest.Costa had no complaints when he was booked for a poor lunge on Gardner after losing control of the ball.Kenedy next powered down the left and Costa looked to join the attack, only to tumble in front of Yacob.The Baggies midfielder avoided punishment, prompting Chelsea complaints led by captain John Terry
Yacob did go off, substituted for Saido Berahino.Chelsea continued to press, with a deflected Costa effort going into the side-netting.McClean was then booked for squaring up to Thibaut Courtois as the contest became more niggly still.Chelsea took the lead for a second time when Willian's cross deflected in off McAuley, who was under pressure from Kenedy.Costa was denied and Kenedy shot wide before McClean equalised from the edge of the area after Chelsea twice failed to clear
Source : PA
Source: PA