When a breakthrough is proving elusive, Liverpool can still prosper from a set piece.

After 75 minutes of caution－even tedium－in the Champions League at Inter Milan, Andy Robertson swung in a corner that was met at the near post by Roberto Firmino glancing in a header, with his back to goal.

It was Liverpool's fifth goal from a set piece in the Champions League this season, ranking first in Europe just like in the Premier League.

Once Mo Salah found the net in the 83rd minute it ensured the six-time European champion secured a 2-0 win in the last-16 first leg on Wednesday.

It was a freekick from Robertson that created the opening for the second at the San Siro as Liverpool scored from the game's only two shots on target.

The host only partially cleared before the ball found its way back to Trent Alexander-Arnold, whose cross into the penalty area was nodded down by Virgil van Dijk. Salah was primed unmarked centrally to produce a shot that deflected past goalkeeper Samir Handanovic for his 10th goal in his last 12 Champions League appearances.

By securing a fourth successive away win in Europe for the first time since 2006, the 2019 Champions League winner gained a crucial cushion to take back to Anfield for the second leg next month.

"Tough place to come, a very good team, difficult to break down and I really enjoyed the atmosphere and the crowd. A good result to take back to Anfield," Van Dijk told BT Sport.

"Everyone expects to be under pressure, it is the Champions League. The message before was you need to be ready to suffer and do the hard work. It is a very good performance, clean sheet and happy days.

"I think we both took a lot of risk in the pressing," Van Dijk added. "It's about the hard fight, the battle when you have the ball－be brave, make the right decisions and keep it tight at the back."

Inter didn't manage a single shot on target in the 90 minutes and now faces missing out on a first quarterfinal appearance since 2011 in European soccer's elite competition.

"I think it was a good match and we should be proud of the way we played against one of the best teams in the world. For 65 to 70 minutes we deserved to win," Inter coach Simone Inzaghi told reporters after the match.

"In the Champions League small details make the difference," Inter defender Milan Skriniar said. "We have created a lot, but we did not manage to score."

How differently it might have turned out for the Italian champion had Hakan Calhanoglu's first-half shot from a tight angle not hit the bar. "We don't have much hope now," Inzaghi said.

"But we will go to Anfield to play the best possible match and we will see."

It was a night when Alexander-Arnold lost his place in the Liverpool record books as the team's youngest-ever Champions League player as Harvey Elliott was handed his first appearance in the competition at 18 years, 318 days.

Elliott played for the first 59 minutes, during which Liverpool were largely underwhelming and came closest to scoring when Sadio Mane headed over in the first half.

The only blot on the trip was Diogo Jota being forced off at halftime with an ankle injury, although that paved the way for the arrival of eventual scorer Firmino.

"Firmino needed time to get into the game," Liverpool manager Jurgen Klopp told BT Sport. "After his goal you could see the confidence back. All of a sudden, the ball was our friend again and we won the game."

The night's other first leg produced a far tighter result with Bayern Munich needing a goal from Kingsley Coman in the 90th minute to recover a 1-1 draw at Salzburg.

The last eight now looks a step too far for Inter after making the last 16 of the Champions League for the first time in a decade, leaving Juventus as Italy's only real hope of success in the competition.

Unlucky Inter

Inzaghi's side started with all the enthusiasm expected of a team back in the knockouts after such a long time away, and Lautaro Martinez got the crowd on their feet in the fifth minute with a long-range effort which flew just wide.

Liverpool responded almost immediately and established territorial dominance, with a Salah shot blocked and Thiago Alcantara shooting over from the edge of the box.

However, it was Inter which had the best chance of the half through Calhanoglu, who after being fed by the rampaging Ivan Perisic let off a shot from a tight angle which beat Reds goalkeeper Alisson Becker but smashed off the bar.

The host was unlucky again 10 minutes later when, after being sent charging down the right flank, Denzel Dumfries flashed over a low cross which was cut out just as it looked destined to find the feet of an unmarked Edin Dzeko.

Inter came out with the bit between its teeth after the interval and swarmed over a clearly flustered Liverpool but again could not get past Van Dijk and company, who kept getting a foot or head in just as danger seemed imminent.

Perisic hung over a beautiful cross in the 52nd minute which Martinez could not quite get to, and a similar pattern was repeated several times with Liverpool rebuffing an increasingly frustrated Inter team unable to convert its supremacy into goals.

The away side punished it with its first proper chance of the second half, Firmino beating Alessandro Bastoni to Robertson's 75th-minute corner and guiding his header past Samir Handanovic.

Perisic flashed a long-distance effort just over but then Salah gave Liverpool a huge advantage eight minutes after Firmino's opener with a fortunate strike which squirmed in and gave the Egyptian an incredible eighth goal in seven Champions League games this season.

Agencies