Chelsea boss Frank Lampard says it is a "shame" Unai Emery was sacked by Arsenal after giving his all for the club.

Arsenal announced the 48-year-old's exit on Friday following a seven-match winless run that culminated in Thursday's 2-1 Europa League home loss to Eintracht Frankfurt.

Emery, who lasted just 18 months in the job after succeeding long-serving boss Arsene Wenger, leaves Arsenal eight points adrift of fourth-place Chelsea in the Premier League.

Lampard is sad to see the Spaniard depart but accepts it is part of being a coach.

"I wouldn't say it was inevitable, because nothing's inevitable in football," he said at Friday's pre-match news conference. 

"We're used to a few surprises, especially in the last few weeks. It's not nice. I know the job, I work hard here and everyone wants to be successful. 

"You have a work ethic and an idea, and it doesn't always go the way you want it, and clubs then make a decision. We're all in that category.

"It's a shame because from the outside he looks like a man who gave everything in the role, but now he moves on."

Chelsea's next opponents West Ham are also reportedly considering a managerial change, with Manuel Pellegrini under increasing pressure ahead of Saturday's London derby.

Defeat at Stamford Bridge could spell the end of Pellegrini's tenure, but Lampard insists he will not be any less determined to pick up three points this weekend.

"We all know the ruthless nature of the game now," he said. "Every team, every group of fans, the owner, everybody wants their team to be successful at all times.

"Individually, I understood the ruthless nature of the job being a player and now even more as a manager.

"I will just do my job. West Ham have good individuals, a good team and a good manager. It's a London derby and we have to be ready for them."