"The bowlers will not find it hard to adapt to the different tracks with more bounce in South Africa, but for the batsmen it will be a test after they have played on slow tracks in Pakistan," Gul said.
Pakistan tour South Africa from early January to play three Tests and five one-day internationals.
Gul rocked the West Indies with three wickets in 10 balls on the second day of the final Test, including the scalp of captain Brian Lara for a duck. West Indies are on 191 for six in reply to Pakistan's first innings total of 304.
The Karachi pitch has come under fire from Pakistan captain Inzamam-ul-Haq, who described it as sub-standard, and West Indian opener Chris Gayle, who said he had not seen a worse Test pitch in his career.
All three Tests have been played on slow pitches good for batting. Pakistan lead the series 1-0.
Gul, who has taken 58 wickets in 14 Tests, said the pitch was very slow and the bounce inconsistent.
"But at this level you have to learn to adapt to bowling on different surfaces. I enjoyed the challenge of bowling on it. But it will deteriorate further," the 24-year-old said.
Gul said long hours of studying Lara's batting style had paid off with his prized wicket for a duck.
"We watched his video several times and he tends to shuffle across too much early in his innings. The line and length to him was part of a plan as he is a key player," Gul said.
West Indian opener Daren Ganga, who is batting on 77, said that while the pitch was not a sporting one it was a true test of character.
"I am enjoying the challenge and as all great batsmen have done in the past, you have to prove yourself on all types of pitches. You have to be tested in all conditions," he said.
