Jurgen Klopp keeps focus on Man City as Liverpool put one foot in Champions League semi-final

The former Porto star, signed in January, was booed relentlessly but he responded perfectly in the 87th minute to spare the blushes of Ibrahima Konate, whose mistake just over half an hour after scoring his first goal for the club had gifted the hosts a goal they had barely deserved.

Jurgen Klopp's side had been coasting at half-time in the Estadio da Luz after Sadio Mane's goal doubled the advantage given to them by their centre-back's header but having squandered numerous chances, Konate's legs got tangled as he tried to make a clearance early in the second half and Darwin Nunez capitalised.

It was a goal which significantly changed the game for a long period, as Benfica suddenly looked the better side with Liverpool completely out of sorts, but Diaz had the final word to make the return look slightly more comfortable than it had done.

Klopp told BT Sport after the game that his side had faced a "tough game".

"Coming here in an away game in the Champions League is tough and obviously Benfica fought for their lives.

"Yes we gave them a little bit, we opened the door a bit too much but they deserved the goal as well, maybe we could've defended better.

"They had these counter-attacks, they set deep for the midfield press, won the balls but it's not easy to keep the ball all the time, the further you go the more risk you take and you pass the ball through, you lose it there, they come in front of you and from there they went and have really good players.

"It was a tough game, what I expected, especially when they scored the crowd was there immediately and you know, 2-0 is nothing, it's nice but not more and they scored the goal.

"It was much more open than we wanted, obviously, but in the end we should have scored in the first half, we could have scored a second, the goalie was the best player, he made a couple of really good saves.

"We won it. Two goals up at half-time, not more, not less, so let's keep going."

Victory saw Liverpool, who had lost on their last three visits here, equal a club record of five successive away victories in Europe.

The omens had not been great for Benfica, third in Portugal's Primeira Liga 15 points behind leaders Porto - whom Liverpool had hammered 5-1 and 2-0 in the group stages this season.

Of the six changes Klopp made, the best one was bringing right-back Trent Alexander-Arnold in after almost three weeks out with a hamstring injury.

His pass for Diaz to head into Mane's path for the second goal was a thing of wonder, while the one he delivered for a strangely off-colour Mohamed Salah to race onto but shoot straight at goalkeeper Odisseas Vlachodimos was almost as good.

It was the first time Klopp had started the midfield trio of Fabinho, Thiago Alcantara and Naby Keita, with the latter impressing in attacking areas.

In the opening 45 minutes the midfielder almost operated as a fourth forward, joining the attack to have four shots of his own before the break to underline the visitors' dominance.

That they only had a two-goal lead to their name was nothing short of criminal considering the opportunities which fell to Keita, Diaz, Salah - three times - and Alexander-Arnold.

Konate eventually made the crucial 17th-minute breakthrough when Diaz won a corner which Andy Robertson swung to the far post, where the defender easily out-jumped Everton to beat the goalkeeper with a downward header.

But better was still to come as Alexander-Arnold's crossfield ball was laid on a plate for Diaz to nod into Mane's path and the Senegal international could not miss from close range, going past Steven Gerrard's total of 22 Champions League goals.

Half-time brought another club record as Liverpool went 19 matches without conceding a first-half goal, although they had barely been troubled with Everton coming closest with a shot into the side-netting.

Four minutes into the second half that all changed after Konate's calamity trying to deal with Rafa Silva's low cross.

The goal altered the mood in the stadium and the momentum on the pitch and Klopp's triple change of Roberto Firmino, Diogo Jota and Jordan Henderson for Mane, Salah and Thiago attempted to restore control.

Further Konate misjudgements caused more problems with Alisson Becker first having to parry Everton's low shot and then, after the defender went chasing a ball he could never win, Nunez had a penalty claim rejected after tumbling under Virgil Van Dijk's challenge.

The pressure seemed to be getting to even the best, with Van Dijk's air-kick in the centre-circle a brief moment of concern while Alisson also duffed a couple of clearances.

But just when it looked like frustration would get the better of them, Keita's perfect through-ball allowed Diaz to round the goalkeeper and slot home an angled shot.

On the last two occasions the teams met in the quarter-finals of this competition, in 1978 and 1984, Liverpool went on to lift the trophy and Diaz's goal put them well on their way to the last four this time.