Adri Arnaus and Michael Hoey carded opening rounds of 66 to set the clubhouse target on day one of the Magical Kenya Open presented by Absa.
The event was first played in 1967 but is making its debut on the European Tour this week, with Arnaus making just his 12th Tour appearance at Karen Country Club.
The Spaniard finished second on last season's European Challenge Tour Rankings - with a missed cut at this event - but has made six of eight cuts this season since graduating to the European Tour.
A 67 at last week's Commercial Bank Qatar Masters was his best opening effort so far but he went one better in Nairobi to set the target at five under.
Northern Irishman Hoey is a veteran of 294 European Tour events with five wins and he birdied his last three holes to jump into a share of the lead.
South African Christiaan Bezuidenhout was one of nine players to finish in a tie for second in Qatar and he was a shot off the lead alongside Italian Filippo Bergamaschi and Chile's Hugo Leon.
Romain Langasque was also at four under in the very early stages of his round, a shot clear of fellow late starters Josh Geary and Liam Johnston.
Dismas Indiza delighted the home crowds with a 69 to sit just three shots off the lead alongside South Korean Hyowon Park and England's Jack Senior.
Deyen Lawson has made headlines this season with two holes-in-one in eight events and he was having an impact again from the first group of the day, birdieing the third, fourth and sixth and eagling the driveable par four ninth to turn in 30.
Another birdie on the 11th moved him to six under and into a three shot lead but he dropped seven shots in his next five holes to tumble back.
Bergamaschi had started quickly with birdies on the 11th, 12th and 15th, and Arnaus had gains on the 11th, 15th and 17th.
Leon bogeyed the fourth but hit back with a hat-trick of birdies, joined the lead at the 11th, and another gain on the 12th put him ahead on his own.
Bergamaschi holed a long putt on the seventh to join him and Arnaus made an 18 foot right-to-lefter on the fifth to make it a three way tie.
A failure to get up and down on the eighth dropped Bergamaschi to three under and he was replaced by Bezuidenhout, who did get up and down from the sand on the sixth to add to birdies on the tenth, 15th, second and fifth, and a bogey on the first.
Leon birdied the 17th to hit the front on his own and Bergamaschi took advantage of the ninth before a Leon bogey on the last meant there were four players tied for the lead.
Arnaus then became the latest player to capitalise on the 332 yard ninth and he jumped out in front on his own.
Hoey bogeyed the seventh but made a hat-trick of gains from the ninth and then rattled off three more in his big finish.
Indiza started birdie-birdie from the tenth but a hat-trick of bogeys from the 12th stalled his progress before the putter got hot on the front nine.
The 50 year old made a 15 foot put for a birdie on the fourth, holed from similar distance on the next to save par, and then cosied up to the hole from distance on the par five sixth to birdie again.
Another birdie on the seventh then had him within touching distance of the leaders and he parred his way home.
Park eagled the 11th to go with three birdies and three bogeys, while Senior made four birdies and two bogeys.
A minute's silence was held at 8.44am to honour the 157 people who lost their lives on Ethiopian Airlines Flight 302 on Sunday.
