José Mourinho made little attempt to hide his delight at hijacking Tottenham Hotspur's move for Willian as the north London club raged behind the scenes about Chelsea's £32m capture of the Anzhi Makhachkala forward representing a vendetta against them.

Chelsea are confident that they will complete the transfer next week, subject to the Brazilian being granted a work permit, after the club's owner, Roman Abramovich, made a personal call to his fellow Russian oligarch, Suleyman Kerimov, the Anzhi owner.

Tottenham, who had seen off competition from Liverpool, thought that Willian was about to sign for them in a £30m deal after he completed a medical on Thursday. However, Abramovich finessed his contact with Kerimov and, to Tottenham's fury, Willian was on his way to Stamford Bridge, albeit for a slightly higher price. Tottenham, Mourinho suggested, had paid the price for not doing the medical "in secret".

The Tottenham manager, André Villas-Boas, who made an unsuccessful move for Willian in January, before the 25-year-old left Shakhtar Donetsk for Anzhi for £30m, had intended to make the player his principal threat in the line behind the striker; somebody to offset the anticipated departure of Gareth Bale to Real Madrid. Tottenham have now intensified their efforts to finalise a deal for Roma's £25m-rated forward Erik Lamela. That is understood to be close.

In the wake of Willian's U-turn, the complaints from White Hart Lane were loud and sustained. Daniel Levy, the chairman, was, according to sources, incandescent and there is the firm belief at Tottenham that Chelsea did not truly want Willian. Instead Tottenham feel that they have moved for him purely to prevent Villas-Boas from constructing a squad to challenge them in the Premier League this season. Chelsea deny this and insist they have always had an interest in Willian.

Tottenham also feel that Willian had no say in the transfer, that it was down purely to Abramovich, Kerimov and the player's advisers. Mourinho already has an abundance of options for the positions behind the striker, in the form of Eden Hazard, Oscar, André Schürrle, Juan Mata, Kevin De Bruyne and Victor Moses, and this has only increased the sense at Tottenham that Willian is not really needed at Chelsea.

The bad blood between the clubs was evident two summers ago, when Levy refused to sell Luka Modric to Chelsea in the face of a £40m offer and the midfielder's desire to go. Abramovich does not like Levy, while there is friction between Mourinho and Villas-Boas. They worked together at Porto, Chelsea and Internazionale but the relationship has soured. Their rivalry this season will be intense.

Chelsea strongly dispute Tottenham's version of events. They maintain that there is nothing underhand about their actions and it is understood that they have been looking at Willian long before this summer, almost signing him from Shakhtar two seasons ago. Although they were unable to reach a consensus over his value then, they have continued to target him and were considering making a bid earlier this summer. In the end it was Tottenham's proactivity that sparked Chelsea into action.

Mourinho's gloating will have done little to soothe Tottenham's anger. Rather than apologise for disrupting their plans, he revelled in snatching Willian from under their noses. He was initially vague, simply saying that he believed that the player had made his decision but when he was asked if that meant that Willian had chosen Chelsea, he made no effort to keep up the pretence. Instead he laughed and nodded.

Mourinho, who still wants to sign Wayne Rooney from Manchester United, said that the episode highlighted the danger of clubs conducting medicals before a contract has been signed, adding that this is why he prefers transfers to be done in secret. "That's the danger of medicals before contracts but, at the same time, if the contract and the medical after sometimes you can have a problem before signing a player so you have to do the medical before," Mourinho said. "The best thing you can do is do the medical in secret. The player is fine, you can sign him. The player is not fine, you don't destroy his career by saying the player has problems, so you do it in secret and after that sign the contract with the club and the player. Sometimes you don't make it. Sometimes you guys have great sources, find everything, but that's the risk."

The former Real Madrid manager was unable to resist one last dig at Tottenham. Asked whether he expected the deal to be completed without any complications, a mischievous grin spread across his face. "We have to do a medical," he said.

Mourinho did, however, sound a word of caution. "I don't like to speak before time because football can be crazy and this is the problem when we speak a lot about names and transfers," he said. "Sometimes it looks like he is but it isn't. But I know what the player wants, so we cannot hide."

Chelsea will have a surplus of attacking midfielders once Willian arrives and Mourinho, who wants a 22-man squad, said that players will leave before the transfer window shuts. However, while Demba Ba and Moses are potential casualties, Mourinho said Mata will not be sold, despite doubts remaining over the Spaniard's future at Stamford Bridge.

"He's a player we all like, he's a player we all want to keep," Mourinho said. "We want more quality in the team, we don't want less quality. We want to add quality to the quality we have. So Juan is not a player we want to lose. The point is not to sell, the point is I want a 22-player squad. So if somebody comes, do we need to sell? No, we don't. Do we need to loan? Probably yes because I don't like to work with big squads. I think 22 is a perfect number to answer to our needs in four competitions."

Despite that, Chelsea will still press ahead with their attempt to sign Rooney, which will add to the intrigue when they face United at Old Trafford on Monday night. United have already rejected two bids from Chelsea for the unsettled striker and Mourinho has said that he will wait until after Monday to make a third offer.

However, he rejected suggestions it would be strange to watch Rooney against his side. "I played against him with Real Madrid, with Chelsea and with Inter and the emotion is we have to be worried with a good player, but no more than that," he said.