A CNN poll of the U.S. vice-presidential debate watchers released following Thursday’s matchup between Republican Paul Ryan and Vice President Joe Biden showed 48% of respondents named Ryan the winner and 44% said Biden won.

The margin between the two candidates was within the poll’s five point sampling error.

A poll taken immediately after last week’s first presidential debate showed a much more decisive victory for Mitt Romney.

Sixty seven percent of debate watchers questioned said that the Republican nominee won the faceoff, with one in four saying that President Barack Obama was victorious.

Vice-presidential candidates Joe Biden and Paul Ryan have begun their one and only debate, as polling show the US election race tightening.

Vice-President Joe Biden and Paul Ryan, a Wisconsin congressman, clashed for 90 minutes at a college in Kentucky.

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