Firstly, congratulations to all of the SA candidates who won their elections last week, and congratulations and good luck to those involved in runoff elections.
While Kyle Boyer got intimidatingly close to the 40% margin required to forgo a runoff election, falling only two votes short of an outright victory and garnering over 16% more of the vote than chief runner-up Julie Bindelglass, his stellar performance in the first round elections should not be construed by anyone as a guarantee of success in the runoff, especially to his campaign and strong supporters.
Runoff elections provide a classic advantage for underdog candidates. Favored candidates, which I would most certainly contend Kyle was and still is, attempt to build grand coalitions of supporters in the first round election, in hopes of gaining an early win and not having to bother with a runoff election. It's a smart strategy, and it works much of the time. It almost did for Boyer.
However, what heavily favored candidates must be wary of in runoff elections is the support for the multiple underdog candidates coalescing around the one remaining less heavily favored candidate in the runoff election. This, accompanied with diminished turnout, which helps heavily favored and more publicized candidates, and a drop in enthusiasm for the coming election, can all add up to an underdog win, if the underdog candidate mounts an effective campaign.
So, before you write off Julie Bindelglass, or don't vote because you think the result is a foregone conclusion, remember that she can definitely win the presidency if she puts in the necessary effort.
In short, neither candidate can take the other's strengths or their own weaknesses for granted. It will be interesting to see what happens.
Learn more about their campaigns here (Kyle Boyer) and here (Julie Bindelglass).