David Lipsky and Tapio Pulkkanen fired opening rounds of 65 to set the clubhouse target on the first morning of the Volvo China Open.
Lipsky arrived at Genzon Golf Club off the back of a top five at last week's Trophée Hassan II and sitting ninth in the Race to Dubai Rankings Presented by Rolex.
His win at the Alfred Dunhill Championship before Christmas has set the American up for what could be a career best season so far on the European Tour, and he made just one bogey in Shenzhen to get to seven under.
Pulkkanen then birdied four of his last six holes in a bogey free effort to join him at the top of the leaderboard.
The Finn easily kept his card last season after topping the European Challenge Tour Rankings and arrived in China after his best result of 2019 so far in Morocco.
American John Catlin was at six under, a shot clear of English pair Ross Fisher and Jordan Smith, Malaysia's Gavin Green, French duo Benjamin Hebert and Romain Langasque, and Filipino Miguel Tabuena.
With the course softened by rain and little wind around, low scores were the order of the day and at one point there was an eight way tie at four under.
That had dropped to seven when Catlin jumped out of it, adding to birdies on the second, fourth, seventh and ninth with another gain on the 11th.
In-form countryman Lipksy then joined him thanks to an 18 foot putt on the fourth to go with gains on the 11th, 15th, 16th, 18th and third, and a bogey on the first.
Smith had held the 18 hole lead last week in Morocco and he found himself in a share in Shenzhen, making birdies on the tenth, 13th, first and second before rolling in a 12 footer at the sixth.
Catlin jumped out of that three way tie with a gain at the 13th but Lipsky soon joined him courtesy of a 15 foot left to righter on the sixth.
The par five ninth was proving gettable and Smith hit the green in two on his final hole but three putted to join the clubhouse leaders at five under.
Playing partners Langasque and Tabuena were the first players to set the target, with Langasque having a birdie-birdie finish to go with three other birdies, two bogeys and an eagle on the par five 13th.
Tabuena turned in level par but made a hat-trick of birdies from the first, holed a ten footer at the sixth and made the most of the ninth.
Green birdied four of his first eight holes but then bogeyed the 18th, second and fifth - to go with another birdie on the first - before picking up shots on the sixth, eighth and ninth.
They were queueing up at five under and Fisher became the next man to get to that mark, adding to birdies on the tenth, 17th, first and sixth with a gain on the ninth.
Lipsky then became the latest player to take advantage of the par five ninth and he held the lead on his own at seven under, with Catlin parring his way home.
Pulkkanen birdied the second and ninth to turn in 34 but caught fire on the back nine with gains on the tenth, 13th, 14th, 15th and 17th.
Hebert started his round with a bogey but fought back brilliantly, making birdies on the second, third, sixth, eighth, tenth and 15th.
There were 12 players at four under including European Tour winners Sam Brazel, Victor Dubuisson, Scott Hend, Mikko Korhonen, Oliver Wilson and Fabrizio Zanotti.