Merseyside Derby: Dominic Fifield on how important the signing of Mohamed Sissoko for Liverpool has turned out - and how Everton can only wonder what if

David Moyes has spent too long already this season attempting to pinpoint where it has all gone so horribly wrong. This evening, the sight of one who got away tearing into his team will provide a pointer to where the campaign first began to unravel.

Mohamed Sissoko, a player long coveted at Goodison Park, will attempt to wrest control of the 202nd Merseyside derby with Moyes cursing the fact that the midfielder wears red and not blue.

For Evertonians, this is likely to offer painful evidence of just what passed them by. After the staggering success of last season, Moyes's toils this term can be traced in no small amount to the frustration endured with Spanish opponents over the summer.

An inability to see off Villarreal in European qualification cost the Premiership club a place in the Champions League, but the fact that negotiations with Valencia over Sissoko's proposed £5 million transfer were eventually undermined by Liverpool's late £5.6 million interest arguably cost Everton just as dearly.

At 20, the Mali international remains raw, his passing often hit and miss and his tackling overzealous to the extent that he has served two suspensions this season. Yet he brings fizz and energy to Liverpool and, just as significantly, liberates the likes of Xabi Alonso, Steven Gerrard and Luis Garcia.

Everton boast creativity in Tim Cahill and Mikel Arteta but, with Lee Carsley injured and Phil Neville increasingly overburdened, their system has lacked the effervescence a player of Sissoko's drive would have provided.

Moyes missed out on numerous targets over the summer - Craig Bellamy, Scott Parker and Emre Belozoglu among them - but the African's arrival across Stanley Park cut the manager deepest.

"I felt it was a deal which we were very close to completing and we were disappointed not to sign him," said Moyes. "We were completing it for a lot less than Liverpool actually paid for him. I met the boy in Amsterdam and I thought we had a chance but, in the end, I suppose it was a bit like getting gazumped when you're buying a house.

"It's gone now. He had those qualities we were looking for, but we were in for a lot of players in the summer. For different reasons, some we got and some we didn't."

Moyes left Everton's pre-season training camp in Austria to fly to Holland hoping to secure Sissoko. The deal, the player's agent Jose Segui said at the time, was "practically finalised", though Liverpool had an advantage in their late pursuit.

Not only were they the newly-crowned European champions, but Rafael Benitez was something of a mentor having originally plucked Sissoko from Auxerre's youth set-up, where the teenager, then a striker, had scored 50 times in two seasons. With the African in his midfield, Benitez's Valencia had claimed the Primera Liga and the Uefa Cup.

"We were playing St Gallen in a pre-season friendly just after we signed Momo and we changed all the players for the second half, but one of them picked up an injury and we asked whether we could put Momo on again to make up the numbers," recalled Benitez. "He played the first half as a second striker, but we used him in midfield for the second and it was incredible. You cannot believe how much stamina he has. He runs and runs, averaging more than 11 or 12 kilometres every game, and he gives us power in the middle.

"I like to sign hungry players and, with time, he can be much better than Patrick Vieira, but I don't want to put Momo under pressure. He is improving every day. We knew Everton were trying to sign him but, once we knew he was available, it was easy for us. He has become so important for the team already - when we talk about clean sheets, if you have Sissoko in front of you running all the time, where you would have had to deal with 10 balls, now you only have four coming through.

"It also means that Gerrard or Xabi can think more offensively. Momo is a different kind of player from what we had."

It was the defeat suffered by the Spaniard's side at Goodison Park a little over a year ago which exposed the deficiencies within Benitez's squad. Back then, his attempts to pick a rugged side forced the inclusion of Salif Diao and Neil Mellor. This year, confronted by Everton's aggression, he can call upon Sissoko and Peter Crouch, both current internationals and of clear Premiership calibre.

"There's no way we'll be bullied against Everton," said Crouch. "People say it's the toughest league in the world and the fact we've won eight games on the run shows the steely determination in the side."

The hosts will need to rise to a daunting challenge tonight if they are to deflect that determination. A year ago, Everton beat Liverpool with Carsley's goal to register their first derby win in seven years and move 12 points clear of their rivals in the Premiership. Defeat tonight would leave them 20 points adrift and, potentially, in the bottom three. Increasingly, it looks as if Sissoko made the correct decision.

* Guardian Service