A main one seemed to be Dier, the 21-year-old Spurs defender Jose Mourinho may have encouraged Costa to goad into a foul or two.
Dier ended up receiving a booking before half-time for the north London side and Costa also got a rise out of Walker, among others.
During their clash, however, there was one moment in which the young Tottenham defender seemed to stand up to the Chelsea man and say 'I'm not scared.'
It made for a fascinating image at the start of the League Cup final, although Costa ended up having the last laugh - and not for the first time.
The 26-year-old tucked home Chelsea's second, with it taking a deflection off Walker (it may well go down as an own goal). As for Dier, it looks as though his debut season as a Spurs player will end up trophyless, despite the prize of a stare-down with Costa.