Chelsea were in bullish mood midway through the second half when Willian struck from the edge of the area.
The Blues could have doubled their lead – and indeed Willian twice hit the post before his goal – but were eventually pegged back by Messi.
Andreas Christensen gave away possession in the Chelsea third and quick as a flash Messi was celebrating a tap-in from Andres Iniesta’s centre.
The draw means this last-16 clash is finely balanced heading into the second leg at the Nou Camp.
Full match report to follow…