The centre admits Wales are desperate to meet the expectation created by their World Cup adventures last year when they rocked New Zealand and England before falling to defeat.
But the former rugby league Man of Steel knows Scotland will be just as determined to impress in their first game under new coach Matt Williams.
"It's a massive game for both countries," said Harris, who will win his 22nd cap at the Millennium Stadium.
"Scotland have just had a complete reshuffle of their squad so they are going to want to get off to a flying start.
"But we want to get off to a good start so there should be fireworks out there on Saturday. The first 20 minutes are going to be really tough up front but hopefully things will open up then.
"Scotland are never easy and we are going to have to play extremely well to come up with the points."
Harris believes Wales can cope with the pressure of being favourites having restored the country's battered reputation in Australia.
"There is a sense of expectation in Wales after the World Cup," added Harris, who played down talk of a return to league by saying he hoped to be at Cardiff next season.
"We won three of our pool games and competed well against two of the best sides in the world.
"We are going into a game for the first time in a while as favourites. We want people expecting us to win."