Fernandez signed an eight-and-a-half year contract after a deal of £106.8m was agreed, which is a British transfer fee record.
The 22-year-old was named as the best young player at the 2022 World Cup as he helped Argentina to a memorable triumph.
Premier League
Chelsea complete Fernandez signing for British record £106.8m
7 HOURS AGO
“It’s always difficult to lose a good player in the winter market,” said Schmidt following his side’s 3-0 win over Arouca on Tuesday night.
“But today we showed that we are a good team without him, that we are capable of playing good football without him, that the players are focused on getting the most points, to be champions.
“Benfica is much bigger than a player. We just need players who are happy to play for Benfica, who are passionate.
“We had a player who wanted to leave and a club willing to pay the clause, we couldn’t do anything. We accepted and looked into it.”
In early January, Schmidt labelled Chelsea’s pursuit of Fernandez as “disrespectful.”
Since Todd Boehly took over as chairman in May, Chelsea have spent £270m in the summer and a further £290m in the winter transfer window.
They signed eight players in the latest window including Mykhaylo Mudryk, Benoit Badiashile and Malo Gusto.
Graham Potter has a big task to get the team into a Champions League spot as they are currently 10th in the Premier League after a difficult run.
Transfers
Arsenal and Man Utd top class, Chelsea miss key area, Everton fail – January transfer grades
8 HOURS AGO
Transfers
Chelsea spend big but leaders Arsenal win the transfer window – The Warm-Up
11 HOURS AGO
