London: Ryan Giggs says Alexis Sanchez is a ready-made "superstar" who can give Manchester United a lift as they bid to chase down Premier League rivals Manchester City.
Sanchez on Monday sealed a move to United from Arsenal in a swap deal with Henrikh Mkhitaryan, saying he was "thrilled to be joining the biggest club in the world".
The 29-year-old Chile striker, who came close to joining Manchester City last summer, has signed what is believed to be a four-and-a-half-year contract that will make him the highest-paid player in the Premier League.
It has been widely reported that Sanchez will earn a pre-tax salary of £500,000 ($697,000, 569,000 euros) a week at Old Trafford.
"Manchester United signing Alexis Sanchez is similar to Robin van Persie in the sense that they're getting a ready-made superstar and you're seeing the contribution already with Anthony Martial upping his performances," new Wales manager Giggs said on skysports.com.
"That can happen when top players come in, those around them lift their levels, and there will be some difficult selection decisions for Jose Mourinho.
"However, Sanchez can also play on the right, as he did at Barcelona, so if Martial is flying then he may have to play in a different position, but those sort of decisions are positive for a manager to have to make."
United boss Mourinho said Sanchez would "complete our very young and talented group of attacking players" alongside the likes of Romelu Lukaku, Marcus Rashford, in-form Jesse Lingard and Martial, who has scored three goals in his past three Premier League games.
Giggs, United's most-decorated player, said it was an extra bonus that the former Arsenal man would be able to play in the Champions League -- United play Sevilla in the first leg of their last-16 tie on February 21.