It is no secret that Mourinho has been keen to add to his squad and would have liked to add a defender.
"I'm not confident, I'm not confident and the market closes today so is time at least for me to stop thinking about the market because the market will be closed".
United have endured a hard summer transfer window as they have tried and failed to sign a host of defensive targets, with Tottenham centre-back Toby Alderweireld and Leicester's Harry Maguire among the names on their wish-list.
Jurgen Klopp's Liverpool did reach they Champions League final, which they lost to Real Madrid, but Mourinho is still bristling over the perception of last season as a disappointment for United, who also lost the FA Cup final to Chelsea.
"My view is that first of all is hard for me to believe we finished second", he said, per the Mirror.
Mohamed Salah has looked sharp in pre-season
"My view is that first of all is hard for me to believe we finished second", he added. 'When I listen, when I read, it's hard to believe we finished second because you are capable of making people who finish second (sound like we) were relegated.
Yerry Mina is considered a fall-back option, and while sources say United believe they can negotiate a fair price with Barcelona for the 23-year-old, who has played just six games for the Spanish side, they are refusing to pay what has been described as a "ridiculous" fee to the Colombian's advisers.
Speaking to the Mirror, he said, "I'm a United fan".
"The list that I gave you before of the injured players is an important list and today after training I will speak with that group of players - because everybody is different physically and mentally - and see how they feel they are".
Manchester United and Leicester City will step out on the Old Trafford turf for the opening round of the 2018/19 Premier League season, slightly burdened by the success of the England national football team in the previous summer's World Cup.