His message was clearly understood as the Austrian side staged a terrific comeback to level things at 3-3, courtesy of substitute Erling Haaland's close-range finish, to stun Jurgen Klopp and the whole of Anfield.
Another spectator entered the pitch midway through the second half and was led away by stewards.
Whilst it's inevitable that Salzburg players will be linked to Liverpool considering the two clubs face each other twice this season in the Champions League group stage, there are certainly worse places to shop.
Salzburg have also been charged by UEFA over the throwing of objects by supporters during the game, in which Mohamed Salah struck the victor for the Champions League holders after the Austrian side recovered from three goals down to level at 3-3.
Liverpool's storied history in this competition has been littered with famous comebacks from 3-0 down, but the shoe was almost on the other foot after half-time as Salzburg threatened an incredible recovery. Be more ruthless against Van Dijk, we play with too much respect.
On October 3rd, we carried a report from Calciomercato, who explained the Reds were also keeping an eye on the Hungarian when they face Salzburg. Now it's us against them.
'I still fancied Liverpool because they were playing so well going forward but it got nervy'.
"We have got results but Salzburg could have been different, Saturday (a 1-0 win at Sheffield United) could have been different, so we need to look at that and we need to play better".
"We saw they're good".
Klopp made no jokes when asked if he would ever allow camera to film him giving a team talk at half-time and said he would "leave the club" if he was ever put in that situation. Come on, we have more to offer'.
"That's the truth and that's all I will say about that".
"It's good that we have played against them, we know what we can expect when we go over there". Each ball they won was immediately behind the line.