The Sun are reporting that Jose Mourinho now believes he will be able to sign the Brazilian attacker, who he worked with during his second spell at Stamford Bridge, in a deal worth around £60m.
Willian, who has cut a frustrated figure recently at Chelsea, was the team's standout performer during their catastrophic 2015/16 season and remained committed to Mourinho during what proved to be his final year at Chelsea.
Transfer expert Duncan Castles examined Barcelona's interest in Willian on the Transfer Window podcast, saying: "Does it make sense for Barcelona to buy Willian? What they are looking for is an explosive player to liberate Messi.
"Barcelona are trying to solve the problem for their best player by pursuing a player like Willian, who they think will improve their tactical options.
"There's a potential for Manchester United to come back in there. But the price is high.
"They have to wait and see what Bale's ultimate decision will be in terms of is he going to get game time under the new manager and will that satisfy his complaints with Madrid.
"From Chelsea's perspective, a sale outside of the Premier League would be far preferable."
Willian had remained completely focused to his World Cup campaign with Brazil, but is now believed to be prepared to discuss his future. He appeared to be frustrated with his role at Chelsea under current manager Antonio Conte, who remains in charge at Chelsea, despite huge reports linking Napoli's Maurizio Sarri to the job.
However, with Barcelona also keen on securing a deal for Willian, Mourinho has a lot of work to do in order to finalise this transfer.