I honestly thought this Ashes series would be a challenge for Australia. I always give my 5-0 prediction because that is what's expected of me. Everyone would be disappointed if I didn't. England came here with a big reputation. We heard lots about how this was their best chance to win here since 2010-11, and how this was the worst Australia team since then. No-one expected Australia to be 3-0 up after three Tests.

We can criticise England - and plenty of people have - but we also must give immense credit to Australia for the way they have played. England have now gone 18 Tests without a win in Australia. Sixteen of those games have been wins for Australia. Of the two draws, the one in Sydney four years ago was only because England's last pair managed to hang on at the end of the game. It is almost beyond belief that an England team has gone so long without winning a Test in this country.

I played in a great Australia side and never lost a home Ashes. Even the teams I played in - alongside some wonderful players like Shane Warne, Ricky Ponting, the Waugh brothers, Adam Gilchrist, Matthew Hayden and plenty of others - were occasionally beaten in a Test by the touring English.

I do not believe England's long barren run in Australia is down to the quality of their players. Think of all the men who have been part of England Ashes teams since they last won in Australia. Alastair Cook, Kevin Pietersen, James Anderson, Stuart Broad, Chris Woakes, Mark Wood, Jofra Archer. The list goes on. Joe Root and Ben Stokes, the cornerstones of this current team and two of the greatest to ever play for England, have never won a Test here.

If this long winless streak is not down to ability, it must be down to mentality. So often, I hear the English talk up how difficult it is to come to Australia. Not just what happens on the field, but everything that goes on away from cricket. It's all about getting sledged in the airport, or in restaurants. England players talk about having to take on the entire country, rather than just the Australia team. There is so much discussion about the conditions in Australia - the pitches and the heat. Captain Stokes even admitted it himself when he said Australia is "no place for weak men".

To flip it the other way, Australians see an Ashes tour of England as the absolute pinnacle. It is the series everyone wants to be involved in. Yes, we know it is difficult. The crowds can be hostile and the Barmy Army are pretty good when it comes to sledging with witty songs. Alongside that difficulty are some of the most enjoyable times to be a cricketer for Australia. As a bowler, I loved getting the Dukes ball in my hand. It was always so special to play at Lord's. I would relish a tour to England.

Can England players get themselves into the state of mind where they relish a tour of Australia, rather than talking it up as the hardest thing they will ever do? There is certainly a difference in mindset between the two countries.

I've heard a phrase a lot over the past few weeks, one that comes up when England seem to be threatening to do well. "It's the hope that kills you." Honestly, that saying does my head in. It does not take much for English hopes to be raised swiftly, only to be dashed more quickly. I can't understand why anyone would ever lose hope. In my life, with everything I've been through, I know that human beings always have to hope. That is the Australian mindset I'm talking about. We are not 'win at all costs', but we never give up until the last run is scored or the last ball is bowled. We always go out there to give it a red hot crack. My mentality, and that of the team I played in, was a game could be won from absolutely any position.

Can England remove those mental blocks before the next Ashes in this country in 2029-30? Before then, they have two more opportunities to end their winless streak, with Tests in Melbourne and Sydney. In my last column, following England's loss at the Gabba, I said they needed to win the third Test in Adelaide, or this tour could get embarrassing. England did not win at the Adelaide Oval and are now facing a huge challenge to avoid being beaten 5-0.

Towards the end of the third Test, England at least showed a willingness to adapt their style, which meant they were able to compete. Why it took them two defeats to realise that will remain a mystery. Still, the signs for an improved performance in the fourth Test are good. However, if we're talking about mentality, it will not get any easier for England. They are due to play in front of 100,000 spectators at the Melbourne Cricket Ground, most of whom will be firmly behind Australia. The Boxing Day Test is an institution in Australian sport and the atmosphere on Friday will be electric.

It will be a tough place to be an English cricketer. England should embrace the challenge, react to it and enjoy it. It could be a valuable lesson for the players who come back to Australia in four years. There is still time for England to salvage something from this tour. Right now, there is a lot of discussion about futures, of who might still be involved when England next play Test cricket in their home summer. Those debates will lose their venom if England can end their winless run here. Losing 3-2 would be so much better than losing 5-0. If England do not find a way to alter their mentality, then 5-0 is the most likely outcome.

Glenn McGrath was speaking to BBC Sport's chief cricket reporter Stephan Shemilt.