Niko Kovac cited Borussia Dortmund's improved speed on the ball in the second half as pivotal in their Champions League play-off victory over Sporting CP on Tuesday. 

After a goalless first-half in which Dortmund registered just one shot on target at the Estadio Jose Alvalade, the Bundesliga side came out after the break a different team. 

Two goals in eight minutes from Serhou Guirassy and Pascal Gross put Dortmund in control before Karim Adeyemi sealed the win in the closing stages of the contest. 

Indeed, Guirassy's strike has now seen him involved in 13 goals in the Champions League this season (10 goals, three assists), the most ever by a Dortmund player in a single campaign in the competition.

Kovac, taking charge of his first Champions League game for Dortmund, also extended his impressive run in the competition away from home. 

He is now unbeaten in each of his seven Champions League away games (W4 D2 with Bayern Munich, W1 with Dortmund), the most matches a manager has taken charge of on the road in the competition without suffering defeat.

Dortmund struggled in the opening exchanges of the contest, registering an expected goals (xG) total of just 0.26 from their six shots, but that metric significantly improved after the interval. 

The visitors registered an xG total of 1.55 from their 10 attempts to Sporting's 0.2, while also recording 12 more touches in the opposition's box than they did in the first 45 minutes.

"You cannot come here and dominate against Sporting, but in the first half we were far too slow," Kovac said.

"After the break, we increased speed and scored great goals. I was happy to see that physical commitment. To play here like that is not easy.

"Sporting are a good team, and we saw it in the first half. We did not have the initiative. We had to play faster, circulate it with fewer touches.

"We took the right decisions, not only when we scored. We could have scored maybe one more goal.

"On Saturday we go to VfL Bochum, and we will face a tough task there. We now have to keep going," added Kovac, whose team are in 11th place in the Bundesliga.