Republican Mehmet Oz's Senate campaign in Pennsylvania raised $17.2 million between July and September — including $7 million from Oz's own money — a campaign official tells Axios. These are big numbers and reflect a high-stakes race that may be narrowing by the minute.

Why it matters: The open seat is shaping up to be the majority-making race for the U.S. Senate. Strategists from both parties agree the race is going down to the wire.

• Oz's Democratic challenger, John Fetterman, hasn't released his latest fundraising numbers yet. But he's been one of the party's most prolific fundraisers. He brought in $11 million in the last quarter.

By the numbers: Oz's third-quarter numbers are an exponential increase from the previous quarter, which partly overlapped the primary election contest and in which Oz raised $5 million, of which $3.2 million was a personal loan.

What we're watching: The battle to succeed retiring GOP Sen. Pat Toomey is one of the most expensive battlegrounds in the country. The latest round of public polling shows Fetterman's double-digit advantage over Oz this summer shrank to a statistical tie.

• Fetterman has held a sizable fundraising advantage over Oz in the race, but Republican outside groups have closed the gap.
• The McConnell-aligned Senate Leadership Fund has spent or reserved $34.1 million in Pennsylvania Senate ads, according to SLF spokesman Jack Pandol, mostly on spots attacking Fetterman's record on crime.