Abdul El-Sayed won Michigan’s Democratic nomination for the U.S. Senate on Wednesday, narrowly defeating U.S. Rep. Haley Stevens in a closely watched battleground-state primary, according to The Associated Press and Reuters.

With 99% of the estimated vote counted, Reuters reported El-Sayed leading 48.5% to 47.5%, while AP said his margin was just under one percentage point and that Stevens conceded and pledged her support.

El-Sayed, a physician and former public health official, will face Republican former congressman Mike Rogers in November in a contest expected to play an important role in determining control of the Senate.