Hearts relied on the side which beat Motherwell the previous week and forced a first minute corner, but Liddell cracked a 20-yard shot high over the bar.
Both teams took some time to settle and although Hearts held the upper hand, they were not able to break down a stuffy Clyde defence.
Clyde found it difficult to build up any promising moves and it was dull stuff with little to excite the fans.
There was no sign of Hearts dominating the game and right on the half-hour mark the Edinburgh side fell behind. Slackness in defence allowed Ahern to cross the ball into the middle, where substitute Hood headed home from close range.
That was fair warning to Hearts that they would have to step up the pace, but so far they had been unable to build up any dangerous attacks on a treacherous surface.
There was no urgency about Hearts' play. They were far too leisurely and lackadaisical, particularly in midfield, with the result that they were quite unable to create any reasonable chances.
Five minutes after the restart, however, the Tynecastle men equalised.
Gibson nodded on a long kickout from Brough, and Fraser ran through the middle unchallenged to beat Connaghan with a low shot.
But Hearts were on level terms for only two minutes. Good work by Hood and Clougherty enabled McCabe to trick Liddle, round the advancing Brough and slip the ball into the empty net.
The burst of scoring continued with O'Connor equalising for Hearts for the second time in 56 minutes.
Robertson was given all the time in the world to send over a cross from the left and somehow O'Connor's header from close in went straight through to Connaghan's outstretched arms into the net.
Three goals in six minutes gave the fans something to shout about, and Hearts had certainly livened up in the second half.
O'Connor nearly put Hearts ahead but the ball bounced awkwardly for him on the six-yard line.
Then, Gibson had the Clyde goalkeeper sprawling on the ground to stop a low drive.
Clyde were struggling now to contain the Edinburgh side but there was still danger in some of the home team's raids.