Marco Silva's first pre-season at Everton has flirted dangerously with disaster.

The Portuguese coach, appointed as Sam Allardyce's successor in June, has failed to record a single victory in six summer friendlies after demolishing poor old Irdning 22-0.

Having drawn with Bury and Lille, the Toffees have lost to Porto, Blackburn Rovers, Rennes and Valencia.

And the 3-2 defeat to the Spaniards, in particular, highlighted worrying deficiencies in the Everton defence.

Need for reinforcements

Following that game Silva was unequivocal in how the final days of the transfer window needed to pan out.

“Since the first day if I want to put one central defender in the game we don’t have any,” Silva said. “Mason Holgate has been injured since the first week of pre-season. We lost others [Ashley Williams]. It is one position and it is easy to understand how many we need in that position. We have to sign new players there.”

Silva didn't mince his words. Despite Everton's impressive transfer business under new director of football Marcel Brands, the former Watford boss effectively demanded defensive reinforcements.

Fortunately for him, Brands seems to have been listening. The Merseyside club made a significant moves to strengthen the defence on transfer deadline day, targeting Chelsea defender Kurt Zouma and Barcelona centre-half Yerry Mina, both of whom had also attracted interest from Manchester United.

With Michael Keane, Phil Jagielka and Holgate already in the squad, Everton's flurry of deadline day business leaves Silva with an abundance of talent at the back.

But why sign more than one defender? Well Silva clearly hasn't been overly enamoured with what he has seen during pre-season. The fact he came out demanding centre-backs does not reflect kindly on Keane and Jagielka, who started together in the defeat to Valencia.

Silva is determined to break into the top six or at least securing a seventh-placed finish and was evidently left concerned with how his first-choice centre-halves performed over the summer.

The 41-year-old's intention, as per his comments in July, are to play a 4-3-3 at Goodison Park. That would presumably be comprised of Jordan Pickford in goal, Seamus Coleman and Lucas Digne at full-back, a midfield three of Idrissa Gueye, Gylfi Sigurðsson and André Gomes, and Richarlison, Cenk Tosun and one of Bernard, Theo Walcott or Ademola Lookman forming a formidable looking trident in attack.

That leaves Mina and Zouma possibly being installed as the new defensive partnership, or one of the two settling in next to Keane.

Bolstered back-line

Mina only signed for Barcelona, agreeing a five-year deal, in January. However, the towering Colombian has struggled to make an impression at the Camp Nou and managed just five La Liga appearances in the second half of last season.

He more than made up for that during the World Cup, though, with three goals during Colombia's campaign. He also managed an average of 4.2 aerial duels won in Russia as clubs began to contemplate capitalising on his uncertain situation at Barça. Everton did just, paying a cool £28.5million for his services.

Zouma, should the deal be confirmed in time, will be hoping for another fruitful loan spell after spending last season with Stoke City. Although that campaign ultimately ended in relegation, making 34 appearances was an important step forward for the 23-year-old, who missed a sizeable chunk of his fledging career with a knee injury suffered in 2016.

Last season Zouma averaged 1.5 tackles, 1.8 interceptions and 3.2 aerials per game. He also won the man-of-the-match on three occasions and Silva is hoping the Frenchman can offer a similar combination of strength, pace and aerial ability to the Everton back-line.

Although neither Mina or Zouma are known for their ball-playing skills, both are quick across the ground so it may allow Silva to deploy his favoured high defensive line, something which would be stark contrast to the dreary, deep tactics of Allardyce.

Having a swell of options at centre-back also opens up the possibility of a three-man defence, with which Silva has experimented in the past.

Everton's first five games of the season include trips to newly-promoted Wolverhampton Wanderers and Bournemouth and entertaining Southampton, Huddersfield Town and West Ham United at Goodison.

There are no easy Premier League games, particularly when a team is undergoing a significant transformation under a bold new manager, but Silva will be expecting to come away from that opening quintet with plenty of points.

Having Mina and Zouma in a bolstered back-line will certainly help achieve that.