Diego Costa has been in top form for Chelsea this season and former Liverpool midfielder Jamie Redknapp said the Spain player's changed attitude is behind his improved output.
"Last season Diego Costa was intent on making a nuisance of himself at Chelsea, but under [manager] Antonio Conte he is becoming a fine example for young players," Redknapp told the Daily Mail.
"This season he is the center forward who never rests. His work rate is so high — just look at how he outmuscled Gareth McAuley and stole in to give Chelsea another three points against West Bromwich [Albion]."
Costa has scored 12 goals in 15 Premier League games for Chelsea this season, helping propel the Blues to the head of the table, with their 1-0 win on Sunday maintaining their three-point lead over Arsenal.
— Chelsea FC (@ChelseaFC) December 11, 2016
Redknapp said younger players had a role model in Costa, naming Everton's Romelu Lukaku as one who needs help.
"I look at Romelu Lukaku and struggle to put a value on him," Redknapp said. "Lukaku may have scored twice in the defeat by Watford on Saturday, but the Belgian didn't have to work hard for those goals."
"He should be modelling himself on Diego Costa. Lukaku is a battering ram of a forward who needs to be more aggressive and bully defenders."
Chelsea next play Sunderland on Tuesday evening.