Bernie Sanders waves to his supporters before delivering his concession speech Saturday in Henderson, Nev. (Ricky Carioti/The Washington Post)

Sen. Bernie Sanders drastically ramped up his campaign's spending in January as the Democratic primary contest engaged, racing through nearly $35 million as he worked to try to match the infrastructure that former secretary of state Hillary Clinton built over the course of last year.

As a result, even though he outraised her for the first time, Clinton expanded her cash lead by the end of the month. After spending $21.2 million in January, Clinton ended the month with nearly $33 million in the bank. Sanders had almost $14.7 million.

A huge share of Sanders's spending in January — $14 million — went into television ads, outpacing the $10 million that Clinton put into advertising. That helped him get more commercials on the air in Nevada in the run-up to Saturday's caucuses, which Clinton won. Sanders had aired 4,650 spots in the state since January, compared to Clinton's 4,156, according to Kantar Media/CMAG data analyzed by the Wesleyan Media Project.

Clinton still spent more on payroll last month, shelling out $4 million for hundreds of staffers the campaign has brought on. But Sanders more than doubled his spending on payroll compared to last quarter, plowing $2.5 million into staff, up from less than $1 million he was paying monthly at the end of last year.

Democratic presidential candidate Bernie Sanders thanked supporters in Nevada and looked ahead to Super Tuesday, saying that he has "an excellent chance of winning many of those states." (AP)

Anu Narayanswamy contributed to this report.