United’s new number seven completed his move to Old Trafford on Monday in a straight swap deal with Arsenal that saw £35million-rated midfielder Henrikh Mkhitaryan head in the opposite direction.
Sanchez, 29, will now be part of the group Mourinho takes to Huish Park for a fourth-round tie with the League Two Glovers on Friday night.
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“In the Premier League he has shown already the quality he has. We got one of the best attacking players in the world,” Mourinho said of Sanchez.
“I think he’s very important for us because we want to have the best possible players.”
Should he feature at Yeovil, Mourinho may consider Sanchez for a number of different attacking roles having been impressed by his versatility for Italian side Udinese and Spanish giants Barcelona prior to his 2014 arrival in England.
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“Our careers are almost made in the same countries simultaneously, so I know him very, very well,” added former Inter Milan and Real Madrid boss Mourinho.
“I saw him play on the right, on the left, as a striker and behind the striker, these are Alexis’ positions.
“I saw him play in different tactical systems, with different philosophies of different managers, I saw him (be) successful in every country, with every manager, with every system, in every position.”
Having just pulled off one significant coup in the transfer market, Mourinho dismissed the possibility of making another seismic move by bringing Cristiano Ronaldo back to Old Trafford from Real Madrid.
The 32-year-old has again been linked with a return to United, the club he left to join Madrid in a then world-record deal in 2009.
Ronaldo and his Madrid team-mates are experiencing an unhappy campaign in Spain as they trail LaLiga leaders Barcelona by 19 points.
“I think with the moment Real Madrid is having now, I think I should be the last one to add some fuel to the fire,” Mourinho said.
“Madrid is on fire, the results are not good and it’s a club where I worked (for) three years, I care about the club.
“I am the last one to add fire so to put some water on the fire, I would say Cristiano is the kind of player that every manager, club wants but only one manager, club can have – (Zinedine) Zidane and Real Madrid, that’s my feeling.”
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