Foster has had his own early-season struggles in his five years as coach of the Chiefs, memorably going six weeks at the start of last season without a win.
That is why he refuses to believe his side will have a cakewalk at Waikato Stadium tonight against a Highlanders side that has slumped to five straight losses and sits at the bottom of the Super 14 table.
"I don't think people give teams enough credit for how tough this championship is,'' Foster told the Otago Daily Times from Hamilton.
"There is no team that can't beat you on any given day. The Highlanders, in a lot of areas, are doing extremely well. They've had close losses and they've had some unfortunate refereeing decisions.
"Looking at win-loss is black and white but behind that they've played some pretty good rugby. They'll be dangerous.
"We know what it feels like when you're struggling. It can build character, and I'm sure that's a goal for the Highlanders.''
Foster concedes the Chiefs have been a mixed bag and have been fortunate to win half their games thanks to some pressure kicks from first five-eighth Stephen Donald.
Foster has had a horrific injury toll, with Tasesa Lavea ruled out for the season inside the first 15min of a pre-season game against the Highlanders in Invercargill, veteran forwards Kristian Ormsby and Jono Gibbes both sidelined, and backs Richard Kahui, Sosene Anesi, Sitiveni Sivivatu, Brendon Leonard and Jamie Nutbrown all affected by various knocks.
But the Chiefs are getting their wounds patched up, and many believe they will stage their traditional surge in the second half of the season.
The most familiar face in the Chiefs line-up tonight is second five-eighth Callum Bruce, who played two full seasons with the Highlanders before being released to the draft.
Foster has been pleased with Bruce, who exercised an out clause in his Otago contract to transfer permanently to Waikato.
"He's an outstanding young man off the field and a very committed player. That's probably a credit to the environment in Otago that he's come to us in such a good place.''
Foster thought Bruce, like many of the Chiefs, had his best game in last week's win against the defending champion Bulls.
