Amane Beriso leads Ethiopian 1-2 in women's marathon
Beriso, who ran the third-fastest marathon ever when winning in Valencia last December, pulled clear soon after entering the last of four 10km laps and came home in 2:24.23.
Gebreslase took silver in 2:24.34 with Fatima Gardadi unable to contain her excitement after claiming Morocco's first-ever medal in the event with bronze in 2:25.17.
Despite the 7 a.m. local time start the athletes were soon faced with another super-hot day, leading to a conservative pace in the early stages.
A group of six eventually broke clear, before the four Ethiopians in the race worked together to make their move soon into the last lap.
Beriso then forged ever more strongly ahead and split the group, putting 20 metres into Yalemzerf Yehualaw, who herself was clear of Gebreslase.
Gebreslase recovered to move back into second as Yehualaw ran out of steam dramatically, allowing Gardadi to sweep past.
Neither of them, however, were able to make any inroads into the leader and Beriso was an impressive winner.
Lonah Chemptai Salpeter of Israel finished fourth in 2:25.38, with Yehualaw eventually finishing fifth in 2:26.13.
The title caps an incredible nine months for the 31-year-old. When she won in Valencia this year she took nearly six minutes off her personal best to post 2:14.58 - the third-fastest in history - and then finished second in the Boston Marathon in April.
"We knew if we worked together we could get a better result, and we worked well as a team today," said Beriso.
"We got the lead group down to six and then we pushed away with four of us. That was our plan because their was such a strong field. After we got rid of the rest, then it was a battle with my tough teammates.
"We wanted to win all three medals, of course, but that didn't go to plan in the end. We took gold and silver and we are happy with that. It's great to keep the title in Ethiopia's hands. We are a group of top athletes working individually most of the time but before the championships we came together with a women's team coach to prepare for the race."
The men's marathon is on Sunday morning, the final day of the championships when another hot day is forecast.
As a result, the mass participation 10km raced scheduled for Sunday on the marathon course has been cut to 5km.