Harrington won the first set in three straight legs and then won the first two legs of the second set. He was hitting trebles and doubles at will and appeared certain to romp home.
However, the match was halted for minor repairs to a computer showing the scores and Harrington's form suffered a similar hiccup.
"I was going like a bomb," he said, "but after they stopped the match I found it difficult to get going again and I was lucky to win the set."
Ferrell missed 10 shots at doubles as he tried to clinch the second set and Harrington scrambled through on his seventh attempt at a double. With his confidence regained, he took the third set by three legs to one.