Usain Bolt’s preparations for the world championships received a jolt as he struggled to win his penultimate race before defending his 100m and 4x100m titles in London – and then admitted to having “some health issues” with a stiff back.

The giddy crowd at the Golden Spike meeting in the Czech Republic were expecting the full Bolt. The poses, the smiles – and, most of all, the raging afterburners applied halfway down the home straight. Yet when the muscular Cuban Yunier Pérez came alongside him in the 100m, Bolt pressed on the accelerator but could not find his sixth gear.

The 30-year-old still had enough to come through in 10.06sec but Pérez was worryingly close in second, just 0.03 behind. It is the first time Bolt has recorded back-to-back times over 10 seconds in the same season since turning professional, and a successful defence of his world 100m title in a month’s time now looks far from certain.

However Bolt insisted he would be ready for the world championships, which begin on 5 August, saying: “I never worry. I always tell you guys if my coach is not worried, I am not worried. I just need to go to my doctor and get everything checked out to make sure everything is smooth and continue training so when my next race in Monaco comes [in the Diamond League on 21 July], I’ll see where I am at.”

Bolt confirmed he would fly to Germany to see his controversial doctor Hans-Wilhelm Müller-Wohlfahrt, who is known for injecting his patients with calves’ blood in the next few days. “It’s just my back, as always,” he added. “My doctor told me over the years that the older I get the worse it is going to get so I just really have to try and keep it in check. I need to go see him to make sure everything is smooth because it is a bit tight. But I didn’t get injured and that’s the key thing. I am happy about that – it’s just about sorting it out and I should be fine.”

Bolt, however, still looked track-rusty – which was perhaps understandable given that it was only his second race of the season after a sluggish 10.03 sec at the Racers Grand Prix earlier this month. But the stiffness in his back cannot have been that serious given he then spent 45 minutes posing for selfies – before, to the delight of those still in the stadium, taking two practice long jumps.

However his coach, Glen Mills, believes Bolthe still has some catching up to do after missing three weeks’ training while grieving for his friend, the late British high-jumper Germaine Mason. “His preparation is not normally where it used to be at this time, so he certainly has ground to catch up,” said Mills. “A big chunk of his training has been affected.

“It was a big blow; he took it very hard. It affected him in terms of his training because he lost about three weeks of training time, and then getting back into things was slow for him, so I am not sure if he is totally over it.”

The conditions were perfect for sprinting – that much was obvious watching the South African Wayde van Niekerk slip below Michael Johnson’s 17-year-old world best in the 300m earlier in the evening. Van Niekerk, who also took Johnson’s 400m world best in winning the Olympics in Rio last year, blasted out of the blocks and finished strongly in 30.81sec – beating Johnson’s time by 0.04.

Mo Farah sprinted to victory in a 10,000m that was little short of an exhibition given his personal best of 26min 46sec was nearly 30sec quicker than the rest of the field. Farah had aimed to go close to that but he was frustrated by erratic pacemaking, which started off slow and then went too fast. Inspired by chants of “Mo, Mo, Mo”, however, he finished strongly to win in 27:12:10, ahead of Mathew Kimeli, a promising 19-year-old who finished sixth in the Kenyan trials at the weekend, but 26 seconds outside his personal best.

There was a surprise in the 1,000m as the two-time Olympic 800m champion David Rudisha could only finish fourth in a modest field. The Kenyan led around the final bend but faded sharply and was overtaken by his compatriot Nicholas Kipkoech, who came through to win in 2:18.51sec, as well as the Czech runners Jakub Holusa and Filip Sasinek, who even if nothing else happens in their careers, now have a treasured story to tell their future grandchildren.

Eugene 2021 threat

The FBI and the IRS are investigating the decision to award the 2021 World Athletics Championships to Eugene, the BBC reported last night. The city, which is close to Nike’s headquarter’s in Beaverton, was controversially awarded the event in 2015 without a formal bidding process. French prosecutors investigating corruption within the IAAF launched their own inquiry into the awarding of the event in 2015. A spokeswoman for the IAA said she was unaware of the FBI and IRS investigations.