Antonio Conte called on Chelsea to rediscover their ruthless streak after Arsenal left Stamford Bridge with a goalless draw in the first leg of their EFL Cup semi-final.

Four days on from Championship side Norwich City restricting the Premier League champions to a 0-0 stalemate, Chelsea were unable to find a way through against Arsene Wenger's men.

Alvaro Morata's personal goal drought extended to four matches, while defender Andreas Christensen proved ill-suited to the task when two golden headed opportunities fell his way after half-time.

"We shot 20 times. We created chances to score, but we didn't take them," Conte lamented at a post-match news conference.

"I think in the last period we must be more clinical, better offensively. Otherwise, if you don't score, if you're lucky the game finishes in a draw.

"After Norwich it's the second 0-0 in a row. We have to reflect on this and try to improve during training sessions and try to improve in this situation.

"Honestly, I think you must be worried if you don't create chances to score and it becomes very difficult to score. This team in every game creates chances to score.

"This season maybe we're a bit unlucky. We're not so good to take these chances. My speech is not for the strikers. For example, Christensen had two fantastic opportunities to score.

"I think we have to improve with all the players, not only the strikers or midfielders. When you have the chance you have to score, especially in these games."

Conte brought the trialled video assistant referee (VAR) system into play when Cesc Fabregas went down in the area under a challenge from Danny Welbeck late on but referee Martin Atkinson's initial on-field decision of no foul was upheld.

The Italian believes the system has been beneficial following its introduction in Serie A but felt Atkinson did not allow sufficient additional time to account for the VAR delay.

"For sure you have to improve and understand when you start VAR you have to add more time in extra [stoppage] time," Conte added, having seen five minutes added at the end of a half where Arsenal midfielder Jack Wilshere received treatment for an ankle injury on the field.

"In Italy sometimes there are doubts two, three times during a game, extra time is seven, eight, nine minutes."