It could only have been pressure that cost Ronnie O'Sullivan a place in the Grand Prix quarter-finals today.
There was the pressure of not being confident with parts of his game, particularly long potting.
And pressure because of who he was playing and the knowledge of what John Higgins is capable of doing.
Higgins must have thought he was out when O'Sullivan twice had good chances to win the eighth. It was to the Scot's credit that he won the decider in one visit because proceedings had become nervy by this point.
O'Sullivan held a 27-17 lead in previous career meetings prior to the match but a number of those wins had come in the Premier League and smaller events.
In ranking tournaments it is now 11-7 to Higgins.
They have now played ten deciders and won five apiece. They were unlucky to draw each other at such an early stage - the last time they played in the last 16 of a ranking event was at the 1996 Thailand Open.
Today's contest was just what the tournament needed.
But the downside is that we've lost one of the star attractions in the second round.