Chelsea goalkeeper Djordje Petrovic admits he’s been a bit surprised by how well teammate Cole Palmer has done so far this season. There’s been some poor signings made by the club in the last couple of years, but Djordje Petrovic and Cole Palmer belong in the category of successes. In particular, Palmer’s been a revelation since joining from Manchester City last summer. The 21-year-old attacking midfielder has quickly become the poster boy around Stamford Bridge. He’s now up to 12 goals and 10 assists in 32 Chelsea appearances across all competitions. Petrovic, 24, has now showered Blues playm…