Former F1 driver Johnny Herbert has branded Red Bull advisor Helmut Marko's retirement jibe at Lewis Hamilton as a "cheap shot" and "typical Red Bull".
Hamilton has endured a wretched start to the new F1 season despite having scored a podium in the season-opener in Bahrain and finishing fourth in Australia, with the Mercedes underperforming compared to Ferrari and Red Bull.
Having scored only a solitary point in Saudi Arabia, the seven-time world champion hit a self-confessed low point when finishing on 13th at the Emilia Romagna Grand Prix.
Former championship rival Max Verstappen added insult to injury in the closing stages by lapping the Mercedes driver.
Marko suggested after the race that Hamilton may be regretting opting against retiring from the sport over the winter months and reacting to the comments, Herbert told Sky Sports: "What a cheap shot. Typical Helmut Marko and Red Bull to be honest.
"After everything that happened last year - what a battle there was between Max and Lewis and, of course, Red Bull and Mercedes.
"It went down to the wire. The race at the end of the year, as we know, was completely and utterly wrong but it was the man who dominated the last part of the year, that was Lewis Hamilton.
"It just shows that he was on fire at the end of last year."
Red Bull would sign Hamilton
Despite Hamilton's poor start to the year and the statements from both himself and the Mercedes team that they are 'not in the championship fight', Red Bull and Ferrari have both been cautious to write off the current eight-time consecutive constructors' champions.
Reiterating his stance that Marko had gone a step too far with his comments, Herbert added: "Would they [Red Bull] want him in their car? Yes, they would.
"But they know he is a big, big threat for them once Mercedes get everything together and then they start battling for those race wins again."