Chelsea host Newcastle in the Premier League on Saturday, with Maurizio Sarri's side seeking to return to winning ways.
The Blues were beaten 1-0 by Tottenham in the first leg of their Carabao Cup semi-final and have been criticised for their struggles in front of goal.
During Friday's training session at Cobham, Sarri's players, including hugely talented young winger Callum Hudson-Odoi, were tested for their reaction speed.
Other players to take part in the drill included Eden Hazard, Cesar Azpilicueta and Marcos Alonso.
Chelsea are currently in fourth place in the Premier League, ten points adrift of leaders Liverpool.
Striker Olivier Giroud, who featured as a substitute against Tottenham, looked sharp in training, while Alvaro Morata was also in the thick of the action.
Hazard started up front against Tottenham but Chelsea have been heavily linked with a deal for AC Milan's Gonzalo Higuain.
Speaking ahead of the game against Newcastle, Sarri stressed that it is important for Chelsea to become more ruthless in front of goal.
As reported by the club's official website, Sarri said: ‘We need to score.
‘We need to solve this problem. In the last match we played very well, with continuity and with a very good offensive and defensive phase, and with a great performance from a physical point of view - the best of the season - but we didn’t score. We have to work and try to solve it as soon as possible.