The Sunset swing puts Lurie's personal popularity to a practical test. Whether a mayor with strong citywide approval numbers can move votes in a district-level race is a different question than whether voters like him at a press conference.

Meanwhile, money is moving elsewhere on the board map. Garry Tan — the tech investor who has backed a slate of candidates in recent cycles — has begun spending in competitive supervisor races. Connie Chan, who represents the Richmond District, has received a significant boost from an outside PAC. Neither the Tan expenditures nor the Chan PAC funds have been publicly detailed beyond initial reports, and the full picture of who is funding what will come into focus as campaign finance filings accumulate.

The early spending is a reminder that the November board races are already being contested at the donor level, even as most voters aren't paying attention yet.

What to watch: Campaign finance filings with the San Francisco Ethics Commission will show the source and scale of PAC contributions to Chan and the targets of Tan-aligned spending. The next major filing deadline will offer the clearest snapshot of where outside money is placing its bets before the election season fully opens.