Polling agency YouGov conducted a survey shortly after the two leaders went head-to-head on ITV which showed 51 per cent of viewers thought Johnson came out on top.
Corbyn was only two percentage points behind the Prime Minister on 49 per cent.
A total of 1,646 viewers were asked: "Leaving aside your own party preference, who do you think performed best overall in tonight’s debate?"
The numbers contrast with another YouGov poll conducted earlier on Tuesday which asked how people thought Mr Johnson and Mr Corbyn would perform later on.
A preliminary survey showed that the public expected Boris Johnson to win by 37 per cent to Jeremy Corbyn's 23 per cent.
A separate poll conducted by Yahoo News on Twitter in the immediate aftermath of the broadcast showed that around 67 per cent of people felt Jeremy Corbyn had won, with the Prime Minister on just 37 per cent.
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Other figures collated by YouGov in the wake of the debate showed 45 per cent thought Jeremy Corbyn appeared “trustworthy” compared with just 40 per cent for Boris Johnson.
However, just 24 per cent of respondents felt the Labour leader’s performance was “Prime Ministerial”, as opposed to 54 per cent for Mr Johnson.
A total of 37 per cent described Mr Corbyn as “likeable”, 17 points behind Mr Johnson on 54 per cent.
While 59 per cent of people thought Mr Corbyn appeared “in touch with ordinary people” compared to just 29 per cent who felt the same about the Prime Minister.