The veteran striker explained how the Spaniard’s intensity on the training ground has forced players to raise their game since his arrival during the World Cup break.
Wolves, bottom of the table when the domestic season resumed, have taken seven points from the next five matches to climb out of the relegation zone, albeit only on goal difference.
Costa explained: “The new coach has had a positive impact and has motivated us, which is notable.
“It’s not like we were lacking in motivation but I think we’re working well and this is what we need to keep doing.
“We’re not in a position we hoped to be in but we’ve got great players, so we need to keep doing what we’ve been doing, and I think with new signings we’ll be able to stay up.”
New signing Craig Dawson reckons Lopetegui’s energy on the touchline makes it feel like his team is playing with an extra man and Costa, yet to score since joining Wolves as a free agent in September, echoed those sentiments.
He added: “Lopetegui conveys a lot of energy, it’s like he’s playing alongside you.
“He’s really intense in training, we get no rest, he’s always asking us to run more. I think this has had a big impact on us.
“He’s also tactically very intelligent, but the intensity he applies in training, always asking us for more and more, and that sometimes leaves you feeling a bit worn out, a bit lazy, but he’s always at you.
“I think that’s something which has been really notable for us players since his arrival.”
Costa also backed another new arrival, Matheus Cunha, to have a big impact over the coming months. Cunha became Lopetegui’s first signing when he arrived from Atletico Madrid in a £43million deal and will compete with Costa and Raul Jimenez up front.
“Matheus is a top-class player,” said Costa. “I don’t know why he couldn’t have stayed at Atlético because he’s such a good player, he was in with a chance of playing in the World Cup.
“He’ll definitely be able to help us a lot if he adapts quickly. I think that the Premier League suits him down to the ground and he’s happy here, he was needing a change of scene, and I think his transfer suits both him and us.”