Darwish, 27, from Cairo, is the 13th player in history to top the men's world list, but only the second Egyptian.
After winning no events at all in 2006, Darwish claimed a single PSA Tour title the following year. But it was in 2008, which he began ranked eight in the world, that the former world junior champion - hitherto largely overshadowed by fellow countrymen like Shabana and Ramy Ashour - made his mark: Darwish reached six finals (including the World Open in England in October) and secured three titles, including his first Super Series crowns at the Qatar Classic and Saudi International.
It was his victory in last month's Saudi International - the richest event of all time, in which he scored his second win of the year over Shabana - that clinched Darwish's world-ranking breakthrough.
"This is the greatest moment of my career," said Darwish after winning the Saudi title which guaranteed his world number one status. "I've been working really hard all my life to reach this moment - thank God I should do it in this, the richest tournament ever."
Shabana slips to two in the new list - but World Open champion Ramy Ashour remains at No3, thus maintaining Egypt's unique hold on the top three ranking positions in the world!
Frenchman Gregory Gaultier, runner-up to Darwish in the Saudi International, holds onto fourth place, with England's James Willstrop at No5 and Australia's British Open champion at six.
Malaysia's Ong Beng Hee begins 2009 in the top ten after moving up two places from 12.
Three players boast career-best rankings in the lower half of the top twenty - Pakistan teenager Aamir Atlas Khan rising to a best-ever 15, and Australian Cameron Pilley also moving up a single place to claim a first-time 17th place. 
But Botswana-born Englishman Alister Walker - outside the top thirty a year ago - celebrates his maiden appearance in the top twenty by jumping three places to No18. 
1[2] Karim Darwish EGY
2[1] Amr Shabana EGY
3[3] Ramy Ashour EGY
4[4] Gregory Gaultier FRA
5[5] James Willstrop ENG
6[6] David Palmer AUS
7[7] Thierry Lincou FRA
8[8] Wael El Hindi EGY
9[9] Peter Barker ENG
10[12] Ong Beng Hee MAS
11[11] Adrian Grant ENG
12[10] Nick Matthew ENG
13[13] Mohd Azlan Iskandar MAS
14[14] Borja Golan ESP
15[16] Aamir Atlas Khan PAK
16[17] Laurens Jan Anjema NED
17[18] Cameron Pilley AUS
18[21] Alister Walker ENG
19[19] Stewart Boswell AUS
20[22] Olli Tuominen FIN
Issued by iSPORTmedia

Egypt's Karim Darwish is number one for the first time in the new January Dunlop PSA Men's World Squash Rankings published by the Professional Squash Association - ending the 33-month reign of his illustrious compatriot Amr Shabana.