Jose claimed that signing the Brazilian is “impossible” as Barcelona will not lose Neymar.
The 25-year-old has been heavily linked with a move to Old Trafford, but the Portuguese tactician has shut all such reports.
Mourinho claimed that any such transfer would be very difficult to pull off with Barca desperate to keep hold of their star man.
“I always try to be objective and pragmatic with the clubs and ask the clubs what can be given to me,” he told ESPN Brasil.
“Neymar is absurd. A club like Barcelona cannot and will not lose Neymar.”
“Although [Lionel] Messi is still a young player with years to go, he is already playing well at 30.”
“Neymar will be the great player of Barcelona after Messi. I think it [signing Neymar] is like trying to break into a safe. Impossible.”
Neymar is going through his worst season at the Camp Nou since making the move from Santos in 2013/14.
Earlier sources had claimed that Manchester United had held talks with Neymar’s representatives and are ready to offer the Brazilian a mammoth wage packet of £416,000-a-week after tax.
Manchester United were reported to offer him a better “financial and football opportunity” than what he gets at the Spanish club and the Red Devils are also more than ready to match his £173 million buy-out clause.
Barcelona return to La Liga action as they look to cut the gap on La Liga leaders Real Madrid.