Republicans in a major swing state have chosen Senator Ted Cruz (R-TX) over Donald Trump Sunday, despite Trump leading in most national polls. 

Cruz has a 10-point lead over Trump in Iowa, the Bloomberg Politics and Des Moines Register poll reveals – an important statistic in the state which begins the primaries voting process for the 2016 presidential race. Iowa will hold a closed caucus on February 1. 

31% of respondents preferred Cruz, vs. just 21% who would vote for Trump, the poll revealed. 

Analysts predict an even tighter race based on the poll’s results, noting both Trump and Cruz have been campaigning heavily in Iowa. 

Trump may have also jettisoned support from the Register‘s readers, BBC reports, after he demeaned the paper, calling its head political reporter “the worst.” It is unclear whether his remarks had a direct impact on the poll results.