Sissoko has the power as Liverpool show depth

The Mali midfielder's first goal for the club put Liverpool on the way to a comfortable victory which was rubberstamped by Andriy Voronin's late second.

Super strike: Mohammed Sissoko has given Liverpool a vital half-time lead

But manager Rafa Benitez's obvious delight was clouded by injuries to central defensive pair Jamie Carragher — taken to hospital for X-rays on a suspected broken rib — and Sami Hyypia, who suffered a broken nose.

Sunderland manager Roy Keane said: 'They just had too much for us. They have great strength in depth. We showed bits of quality but it just wasn't our day. On days like this you have to take your medicine.'

The Liverpool boss was equally phlegmatic, saying: 'We played well and had a lot of chances, but at this stage of the season it was important just to win. I think we have a stronger squad now than last season.'

Liverpool spent almost as much on Fernando Torres as Sunderland's total summer budget, so it would have been an affront to the logic of football economics had the Premier League newcomers been able to hold their own here.

Liverpool needed little invitation to assume control,having almost grabbed a lead in the opening seconds. Greg Halford's carelessly struck backpass for Craig Gordon was pounced on by the eager Voronin.

His effort almost squeezed through Gordon's legs but the keeper got enough on the ball to stop it crossing the line.

It was the first of a chronicle of saves by the former Hearts man, who ably demonstrated why Keane pursued him doggedly before making him the most expensive goalkeeper in British transfer history at £9 million. Gordon is surely worth every penny.

Sunderland were never short of effort and enthusiasm, typified by the nonstop energy of lone striker Michael Chopra, who chased and harried with little reward against a visitors' defence superbly marshalled by Carragher — before he went off with quarter-of-anhour left.

The former England international lost central defensive partner Hyypia after 15 minutes when the Finn damaged his nose in a clash with Daryl Murphy, indicating as he went off that he thought the striker had used his elbow during the challenge.

The blip was easily accommodated by the Merseysiders, who rarely gave the home supporters hope.

Sunderland had one chance,however, when Liverpool were caught square by Chopra's through-ball for Anthony Stokes.

But the Irishman — a 19th-minute substitute for the injured Kieran Richardson — could not shoot powerfully enough to prevent Jose Reina making a one-handed save.

A Liverpool goal was almost inevitable and the wonder was that it took them until the 37th minute.

Xabi Alonso picked out Jermaine Pennant at the far post and the winger nodded the ball back to Voronin, who rolled it into the path of the advancing Sissoko.

For once Gordon was not equal to the task of preventing the Liverpool player's powerful shot crashing into the left-hand corner from 25 yards.

You sensed the points were as good as won and only the heroics of Gordon kept the game in the balance until Voronin put the issue beyond doubt four minutes from the end.

The Scot denied Torres a second Premier League goal in first-half injurytime, diving to keep out the Spaniard's header.

Five minutes after the break the £26million striker was foiled again by Gordon after he had left Nyron Nosworthy and Paul McShane gasping with his blistering pace.

And somehow the goalkeeper stopped Voronin's point-blank shot in the 79th minute after Torres turned provider to lay on the opportunity to strike.

The newly formed Spanish-Ukrainian forward duo have the potential to be the best in the Premier League and there was no hiding place for Sunderland when they combined again in the 86th minute.

Six Liverpool players were involved in a superb counter-attack which ended with Torres feeding Voronin, who beat Gordon with a fierce cross-shot. 'We left it late to clinch the game,' added Benitez. 'It's not good for my heart.'