The public still largely believes the SNP is on their side, according to Nicola Sturgeon's former chief of staff.
Writing in The Herald on the eve of the SNP conference in Aberdeen, Liz Lloyd said Humza Yousaf must capitalise on that feeling to fight against a resurgent Labour party.
Ms Lloyd said: "It seems the public largely continue to believe the SNP, as a team, is on their side; a sentiment that played a significant part in those three special Westminster wins.
"And if Yousaf wants to be the first to show that the SNP can win seats against a resurgent Labour Party, then he might want to start there.
"What he can do, and as a new leader he has to do, is to leave the voters and viewers feeling that the SNP is once again on their side."
Read more: The hill Humza Yousaf has to climb as SNP conference looms - Liz Lloyd
Ms Lloyd, who left politics when Nicola Sturgeon stepped down as First Minister earlier this year, said the coming general election will determine if the SNP can hold a majority in Scotland for "just one 10 year stint" or decades, as the Labour party did previously.
"SNP success in a Westminster election remains very much the anomaly, not yet the rule," she said. And to rely on "constitutional preference alone" would be a mistake.
The former advisor, described as Nicola Sturgeon's "right hand woman", argued voters are both unsure about Labour and the SNP.
And she said the electorate has "not yet heard a vision of how the SNP would work with the widely assumed Labour government".
It comes as the SNP prepares for its party conference in the midst of several crises.
Read more: Get the popcorn, the SNP have gone quite mad
In recent weeks, Lisa Cameron MP quit the party to defect to the Conservatives, an SNP councillor was embroiled in a racism row for which Humza Yousaf had to apologise, and the SNP lost in a crunch by-election in Rutherglen and Hamilton West.
While veteran MSP Fergus Ewing had the SNP whip suspended after he voted against Greens minister Lorna Slater in a vote of no confidence.
And it has emerged this week the SNP is set to change its independence strategy again at its party conference in what Unionists called an "embarrassment".
Ahead of the conference in Aberdeen, the First Minister has made an appeal for party unity or else risk making the independence cause "weaker".
He said: "I don't care if you voted for Kate or Ash, whether they agree or disagree with the Bute House Agreement, let's come together and respect the party.
"That's the party that elected me as leader, it's the party that, of course, overwhelmingly backed the Bute House Agreement with the Greens as well. So, unity is going to be important."
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules hereComments are closed on this article