Scott Quin laid down a marker of intent ahead of tonight’s 100m breaststroke SB14 final by setting a new Paralympic record in his heat.
Edinburgh’s Quin, appearing at his first Paralympic Games, clocked 1:06.65.
The 26-year-old European champion was the fastest overall qualifier, followed by teammate and fellow Paralympics debutant Aaron Moores in 1:07.25.
Quin said: “It’s good to get that heat swim out of the way. I’ve been waiting all week and watching my teammates doing their swims and just wanting to get going myself.
“My coach was telling me just to keep relaxed and to keep chilled. I’m happy with that swim going into the final.”
Jonathan Fox was another to top the timing sheets on Wednesday in the men’s 400m freestyle S7 heats.
The 25-year-old St Stephen swimmer, who has already won silver in the 100m backstroke in Rio, clocked 4:51.10 with teammate Michael Jones also third fastest overall with 4:58.50.
Fox said: “It felt really good. My main event has been and gone. For the past year since I’ve been back in the pool, I’ve been solely focused on the backstroke so this was a bit of fun to come in and race with a teammate.
“I’ll take that for a heat swim and hopefully I’ll drop under 4:50 tonight. I’ve got the experience from three Games for tonight to do a tactical swim. You can’t just go out and smash it like a 50m, you have to be tactical about it.”
Bethany Firth’s strong showing in Rio continued as she won her 100m breaststroke SB14 heat in 1:18.19, with teammate Jessica-Jane Applegate fourth in 1:26.56.
Firth, a double gold medalist in Rio already, qualified through to the final third fastest.
She said: “I just went and tried to enjoy it. I’m looking forward to coming back tonight and giving it a better shot.
“I don’t train breaststroke very often, I can enjoy this one more as I know it’s not one of my main events so I can just go out and see what happens.”
Four-time Paralympian Claire Cashmore was another on form, touching the wall second in her 100m breaststroke SB8 final in 1:25.91 to progress into the final.
She said: “I’m really happy with that, I had a plan this morning and I pretty much executed that so I’m happy.
“It gives me a lot of confidence going into tonight that I can go a lot faster.
“With it being my fourth Games, I’ve put so much pressure on myself and beaten myself up on everything I had done wrong and not appreciated the medals I had won.
“I’ve really come into these Games with a completely different mental attitude and just wanting to enjoy the whole thing. I’ve done the work so the outcome will take care of itself.”
The penultimate British swimmer in action was Stephen Clegg and he also progressed to the final of the 100m backstroke S12 after posting the fifth fastest time overall of 1:03.11
Clegg, whose older sister Libby completed the sprint double at the Olympic Stadium last night, said: “I think I’ve got a lot more for tonight. I had a good strong 50m and then backed off a little bit tonight which is not what I normally do.
“Libby and I are spending quite a lot of time together in the village, we go for lunch together.
“I had a bit of a rough start with my 400m at the start of the week but she talked me through it and managed to calm me down. I watched her race last night and I’m really pleased for her.”
And finally ParalympicsGB’s youngest athlete in Rio, Abby Kane, finished sixth in her women’s 50m freestyle S13 heat in a time of 29.98.