Chelsea head coach Maurizio Sarri and Tottenham counterpart Mauricio Pochettino complained about VAR after Harry Kane's penalty earned Spurs a 1-0 Carabao Cup semi-final advantage at Wembley.

Kane scored from the spot in the 26th minute after being scythed down by Kepa Arrizabalaga, with the video assistant referee ruling the England striker had stayed onside in the build-up.

Pochettino was unhappy, despite benefiting from the decision to give his side the ascendancy in the tie, which concludes with the second leg at Stamford Bridge on January 24.

Pochettino told a post-match media conference: "It's a system that sometimes kills the emotions. Today it was an advantage for us, but I didn't celebrate because we were waiting five minutes."

Pochettino had earlier told Sky Sports: "Of course I am pro-technology because you cannot stop evolution.

"I think it is not clear what are the rules. Before they start to use it I think we need to be clear how we are going to use it and to all agree – the clubs, the players and the coaching staff. If not it's going to be difficult."

Sarri thought the decision was wrong and said the assistant referee's actions in stopping running contributed to his players' belief that an offside would be given against Kane.

"From the image from our camera, Kane was offside, clearly offside," Sarri said. "But it's not important. I think it's more important that the linesman stopped the run, he didn't follow the ball.

"So for the players on the pitch, it's clearly offside. He had a big influence on our defenders."

Sarri had not seen the official VAR footage, only images from Chelsea's own camera.

Sarri added: "Maybe the camera of the VAR was in another position. From our camera it was clearly offside."

In his Sky Sports interview, Sarri questioned whether English referees were able to use VAR properly.

"At the moment I think that English referees are not able to use the system," he said.

"I think they have to study the system. Of course, it's very strange that in the Premier League there isn't and in the Carabao Cup there is the system. Strange for us, the players and I think also the referees."

Kane's spot-kick saw him move ahead of Cliff Jones on Tottenham's all-time list of scorers. He is fourth with 160 goals after netting for the sixth successive game.

It gave Spurs a win they perhaps did not deserve as Chelsea twice hit the woodwork, but there will be no complaints from the hosts as they registered a third successive victory over their London rivals for the first time since 1963.

Pochettino added: "It's only half-time (in the tie). We need to wait. We need to show we are capable of beating them there and go to the final.

"I think the season we're doing is fantastic, but in the same way the effort we're doing is amazing.

"I'm so pleased, I'm so proud to have this squad and to work together. At the end, (whether we) win or not win titles, I always say we need to feel very proud about the players that we have."

Sarri felt Chelsea deserved more from the game.

He said: "I'm really disappointed with the result, but I'm really happy with the performance.

"We played with a very good level of application, of determination, with the heart, with the soul. We played in this way with continuity for 95 minutes.

"Usually in the last matches we defended very well for 60 minutes then we had problems in the last 20, 30, sometimes 15 minutes. In this match the level of application was the same for 95 minutes."

Callum Hudson-Odoi started and performed well amid repeated links with a big money move to Bayern Munich.

Of the 18-year-old, Sarri said: "He is improving. In the last match he played very well and also today I think a very good match.

"He played like a player of 25, 26 years, I think. A very good match."