'We thought: "Come on, let's bring him and have a look in the morning".
After booting five goals in the two Premier League fixtures last season against Watford - which included a debut goal and a mesmerising four goal haul at Anfield - Salah was at it again in his third meeting with the Hornets.
Three goals in just over 20 minutes helped Liverpool to their 10 victory of the Premier League season and maintained their unbeaten start - overpowering an impressive Watford side with a 3-0 win at Vicarage Road.
After a largely uneventful first half, Mohamed Salah put the ball past Watford goalkeeper Ben Foster in the 67th minute before England defender Trent Alexander-Arnold scored a stunning second goal.
Klopp appeared to be ready to replace Henderson with Fabinho before the red card and he conceded that being without the influential 28-year-old for next weekend's game at home to rivals Everton is a blow.
"In a few moments, the tempo change could have been a bit more obvious but even then, we had our chances".More news: Premier League goals: Manchester City, Liverpool continue dominant run, Man United falters
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"It is nice. This fantastic big club has had outstanding teams in the past, so for this group of players to get this record is nice".
This was a game that previous Liverpool teams would have failed to see out, or given away late in a flurry of disorganisation and insipid defending, but under Klopp in 2018-19 they are an entirely new proposition.
'It was a really mature performance.
"I'm really happy about it, to be honest", added Klopp. I'm not sure what the critics were saying about Bobby Firmino after the game, but when I saw the coaches later and we had drinks together, they were like 'Bobby Firmino. what a player!' We never controlled games in the manner we do now. On the other side, we had to stay stubborn as well, we had to pass, to be patient but stay lively and accelerate.
Despite a blistering start to collect 33 from a possible 39 points, Liverpool still trail champions Manchester City by two points.
"The thing is we have to win football games but people compare a game against Watford with a game against Roma". They had moments, they had counter-attacks, you can not avoid that.