LINZ, Austria: Bradley Barcola silenced his critics as the Liverpool forward ended his goal drought with a hat-trick in a chaotic 6-3 win against LASK in the Champions League on Wednesday.
Barcola had come under fire for some lacklustre performances since his blockbuster £123 million ($161 million) move from Paris Saint-Germain in August.
But the France forward finally started to live up to his hefty price tag with his first goals for Liverpool in his seventh appearance.
Barcola struck twice before the interval at the Raiffeisen Arena after Ronald Araujo put Liverpool ahead in the first half with his maiden goal for the club.
Jeremie Frimpong netted the fourth after the break against the Austrian champions before Barcola completed his treble.
There was still time for Lewis Koumas to score his first Champions League goal as Liverpool maintained their 100 percent record in this season's tournament after beating Atletico Madrid in their opening game.
It was a welcome boost for Iraola following his first defeat in eight games as Liverpool manager when Premier League leaders Manchester City won 3-0 at Anfield on Sunday.
Iraola this week said he has "100 per cent" trust in Barcola and Florian Wirtz, who has struggled mightily since joining from Bayer Leverkusen last year.
Injuries to Alexander Isak, Cody Gakpo and Dominik Szoboszlai, who all missed the trip to Austria, increased the pressure on Wirtz and Barcola to carry the Liverpool attack.
The pair repaid Iraola's faith with a much-needed display of their undoubted qualities.
Now Iraola will demand they produce that level of intensity and quality on a regular basis.
The trip to Linz was the second of six games in 18 days for Liverpool, forcing Iraola to make changes in a bid to save his players from burnout.
Reds captain Virgil van Dijk, Milos Kerkez, Alexis Mac Allister and Victor Munoz were all rested as Frimpong, Kostas Tsimikas, Trey Nyoni and Rio Ngumoha came in.
- Clinical Barcola -
After some disjointed displays at the start of Iraola's reign, this was an indication of what they can become under the former Bournemouth boss, although he will still be concerned about their defensive issues.
Araujo put Liverpool ahead in the 22nd minute, rising highest to meet Tsimikas's corner with a thumping header past LASK keeper Lukas Jungwirth.
The on-loan Barcelona defender's goal was swiftly followed by one for Barcola 96 seconds later.
Ngumoha was the catalyst with an incisive run into the LASK area and Barcola applied the finishing touch as he guided a clinical finish beyond Jungwirth.
Iraola's men were running riot and Barcola scored their third in the 37th minute.
It was a riposte to the criticism of Wirtz and Barcola as the pair combined to cut through the LASK defence.
Barcola picked out Wirtz and the German played a pinpoint return pass that allowed the 24-year-old to fire past Jungwirth.
Frimpong has also frustrated Liverpool fans since signing last year, making his goal in the 51st minute a welcome tonic for the Dutch right-back.
Tsimikas got to the byline and lofted a cross towards Frimpong, who belied his diminutive stature with a towering header into the bottom corner.
Robert Ljubicic reduced the deficit in the 63rd minute with a composed finish from Yvan Dibango's pass.
But Barcola sealed his treble with a nimble finish from Frimpong's pass in the 66th minute.
Teed up by Frimpong, Koumas hit Liverpool's sixth with a searing strike in the 72nd minute.
Despite the introduction of Van Dijk and fellow defender Joe Gomez, Liverpool lost control in the closing stages.
Florian Flecker's diving header two minutes later punished slack Liverpool defending.
Flecker struck again with a close-range finish in the 77th minute, but nothing could spoil Barcola's big night.