Andre Villas-Boas has 'lit up' Zenit Saint Petersburg since his appointment as manager of the Russian title chasers, the club's Brazilian striker Hulk claims.
Hulk's hat-trick in Saturday's 4-1 win over FC Krasnodar left Zenit leading the league by one point from Lokomotiv Moscow.
Since Villas-Boas, sacked by Tottenham in December, was appointed last month Zenit have gone on a four-match winning spree.
And Hulk, who has scored seven goals and made five assists in that period, says the credit should go to his former boss at Porto.
"I have the experience of working with Villas-Boas in Porto and I'm happy to work with him again.
"After several weeks here I can say his arrival has lit us up."
The 27-year-old added: "Now we work really hard during the whole week to come into the weekend's match at the top of our form.
"Every day we understand better and better exactly what our manager is expecting from each of us and how we should play."
Hulk, who leads the Russian goal scoring charts with 16, said his sole focus was on winning the league.
"I feel really strong motivation to win the Russian title this season," he said.
"Speaking honestly I would definitely prefer to win the championship than to finish the season as the league's top scorer."
Hulk, who has won four Portuguese titles and the 2011 Europa League with Porto, joined Zenit in September 2012 together with Belgian midfielder Axel Witsel in a reported 100 million euros deal -- the biggest ever transfer in Russian football history.
Yet Zenit have failed to make a breakthrough in the Champions League, last month they suffered a 5-4 aggregate last 16 defeat to German giants Borussia Dortmund.
That loss cost Villas-Boas's Italian predecessor Luciano Spalletti his job at the club owned by Russian state-controlled gas giant Gazprom.