Fueled by a massive advantage in donations from those who gave less than $200, Pennsylvania Lt. Gov. John Fetterman heavily out-raised Republican Mehmet Oz from late April through the start of July, entering the opening act of the general election for U.S. Senate with a significant cash advantage.

Mr. Fetterman’s total haul from individuals and committees, according to campaign finance reports due to the Federal Election Commission on Friday, checked in at $9.9 million. Mr. Oz, the cardiothoracic surgeon and TV celebrity, brought in $1.1 million, closing the gap a bit by loaning his campaign another $2.2 million.

As the calendar turned to July, Mr. Fetterman had five times as much cash on hand as Mr. Oz, at a total of $5.5 million to $1.1 million.

A Post-Gazette analysis of the reports underscored the extravagant stakes of the race, as leadership from both parties starts to descend on the state as a key to control of the Senate. It also showed Mr. Fetterman with a sizable financial head-start and a donor base he can continue to tap into, even as he continues to rest from the campaign trail recovering from a stroke.