Former Leeds United head coach Thomas Christiansen.

Speaking for the first time since his dismissal at the start of this month, Christiansen blamed the suspension imposed on Saiz after Leeds’ FA Cup defeat at Newport County for costing him “our most important offensive player”, claiming Leeds “couldn’t afford” to buy a suitable replacement in January.

Saiz, United’s gifted Spanish playmaker, was hit with a heavy ban by the Football Association after admitting to spitting at Newport midfielder Robbie Willmott in the closing seconds of Leeds’ humiliating 2-1 defeat at Rodney Parade.

Christiansen, despite fielding a weakened team for that third-round tie, had chosen to introduce Saiz as a substitute for the last 15 minutes with Leeds 1-0 ahead. United conceded twice late on and Saiz’ offence came after Newport’s 89th-minute winner.

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United's Samuel Saiz.

His red card was one of four incurred in the space of five games by Leeds, a chronic disciplinary record which left Christiansen facing up to major selection issues.

Leeds failed to win a game in Saiz’s absence and Christiansen was sacked by United owner Andrea Radrizzani on February 4 after 35 games in charge, removed in the wake of a 4-1 defeat at home to Cardiff City.

Speaking to Danish newspaper BT, Christiansen said: “Our best player, Spaniard Samuel Saiz, got a red card for spitting at an opponent in the face as we went out of the FA Cup against Newport. He got six matches out and some of the others also got long suspensions.

“Samuel Saiz was our most important player in the offensive part of the game and we couldn’t afford to buy a new one. Suspensions and injuries piled up. The squad just wasn’t big enough for us to replace those players.”

Leeds United's Samuel Saiz is sent off for spitting during his side's FA Cup defeat at Newport County.

Saiz, who made a public apology, finally completed his ban last weekend and is available for the first time for tonight’s game at Derby County.

His return came too late to rescue Christiansen’s job and United, now under new boss Paul Heckingbottom, are eight points adrift of the play-offs with 14 games to play.

Radrizzani told the YEP a fortnight ago that appointing Christiansen - a coach with three years of prior managerial experience gained in Cyprus - was a “mistake” and admitted he had been tempted to sack the 44-year-old after the defeat to League Two Newport.

Christiansen had taken Leeds to the top of Championship in September with a seven-game unbeaten run but watched his side’s form dip badly in the autumn and again after Christmas.

United's Samuel Saiz.

The Dane admitted that a good start had raised expectations, saying: “It’s a big club which really dreams of moving back to the Premier League where they believe they belong. Every single season the club and its fans believe that now they’re there.

“The club’s fans said the team had not played so well for over a decade. With our good start, expectations grew a little more.”