Shericka Jackson, Stephenie ann McPherson, Novlene Williams-Mills and Christine Day will seek to increase Jamaica’s medal count when they run in the 400-metres final at the world championships tomorrow.

But they’ll have to contend with Britain’s Christine Ohuruogu, Shaunae Miller of the Bahamas and Allyson Felix of the United States.

The race is set for 7:10 am Jamaica time.

Meanwhile, Usain Bolt, Nickel Ashmeade, Warren Weir and Julian forte, are all through to the semi-finals of the 200-metres.