Newcastle United boss Alan Pardew said new recruit Moussa Sissoko had already proved his value after scoring twice in his side's 3-2 victory over Chelsea.
French midfielder Sissoko, 23, has been at the club eight days since signing from Toulouse for a reported £1.8m.
And he has starred in the two games as Newcastle secured back-to-back league wins for the first time since April.
"We accelerated [the deal] because he was going to come in summer and he's paid us back handsomely," said Pardew.
"I don't need to say anything about him because his performance said it all.
"I remember watching him for Toulouse 14 months ago and I thought he is definitely the one for us, if we can get him.
"We watched him and looked at him for a long time and we'd set our sights on him early, which is a good thing."
French international Sissoko, who has signed a six-and-a-half-year contract at Newcastle, has joined 10 French players in the squad.
Speaking through an interpreter, Sissoko said: "It was a fantastic afternoon, we knew it would be a complicated game. We knew we needed to press on after the Aston Villa game and to get two goals was fantastic.
"Ever since I was a child I've always dreamed of playing in England. Playing in front of fantastic crowd like that, I'm happy I scored the goals thanks to a fantastic team performance."
Pardew said Sissoko was the difference in a crucial win over fellow strugglers Aston Villa last Tuesday, but his two goals against Chelsea lifted the Magpies seven points clear of the relegation zone.
Pardew told BBC Sport: "Suddenly you look at us and we can climb the league but this was an important victory. We are going to cherish it because we have had some really rough days."
Sissoko made his home debut in an advanced role in a thrilling match at St James' Park. And his double eclipsed fine strikes by Chelsea's Frank Lampard and Juan Mata after Jonas Gutierrez's header had opened the scoring.
Pardew added: "It was an unbelievable game. Truly, I can't remember seeing a game as good as that.
"We suffered two unbelievable goals against us to find ourselves behind in the game but we weren't to be denied and it was a fantastic end to the game."