Jose Mourinho has revealed the Chelsea squad are 'so happy and so surprised' at Diego Costa's form since he joined the club from Atletico Madrid.
The £32m Spain international joined up with his new squad after the World Cup and has impressed his new teammates on the team's preseason tour of Europe. Costa bagged his first Chelsea goal in the 2-1 win over Olimpija Ljubljana, and he's looked sharp in each friendly game so far.
Perfect striker for Chelsea
And speaking to Sky Sports News, Mourinho admitted his team have been blown away by the performances of the new Chelsea man - something that bodes well for the upcoming season.
"He's a great addition for us," Mourinho said. "He is a fantastic player. Technically he is very, very good.
"That's why lots of the players are so happy and so surprised, because his quality is even higher than what they expect. He's so strong physically and gives so much effort during matches.
"He's a great addition for us. He's a fantastic player. When somebody sees him play the first thing into their eyes is exactly that, the capacity to work hard for the team."
Mourinho complained about his attack last season on several occasions, publicly criticising a lack of killer instinct in front of goal. Eden Hazard was the club's top Premier League goalscorer, as Samuel Eto'o, Fernando Torres and Demba Ba struggled.
Ba has been sold while Samuel Eto'o was allowed to leave on a free transfer. Torres remains, but young forward Romelu Lukaku was also sold to Everton for £28m.
That means Chelsea will start the season with three strikers - Costa, Torres and Didier Drogba. The Ivory Coast legend has returned to the club he won a Champions League trophy with in 2012 after spells in China and Turkey.
But Costa, who struck 36 times in 52 appearances for La Liga champions Atletico Madrid last season, will begin the campaign as Mourinho's first choice.