The 20-year-old USA swimmer last night successfully defended her 100m Butterfly - S8 title and returned to the Aquatics Centre to post notice of her intentions to continue that run with victory by almost 14 seconds in a Paralympic record in her 400m Freestyle heat this morning.
I can honestly say I swam my heart out and I gave it everything I hadJessica Long
Tonight, the American was two seconds ahead after 100m and continued to extend that lead to win in 4:42.28, lowering her own world mark set in June by 1.89 seconds, and finishing more than 18 seconds ahead of Britain's Heather Frederiksen in second.
Long said: 'What I always like to say is I swam my heart out and I can honestly say I swam my heart out and I gave it everything I had.
'That was the goal tonight, to go in and break the world record and that is exactly what I wanted to do.
'I set my goals very, very high and I feel like I'm always competing against myself and setting new goals for everyone. Records are made to be broken.'
Long first competed at the Athens 2004 Games aged just 12 and won three gold medals before securing a further four titles, a silver and a bronze four years later.
Of being a multi-medallist, Long said: 'When I was 12 I had no expectations and then when I was 16 I put a ton of pressure on myself. But now that I'm 20 I have no pressure.
'I don't have anything to prove, I already have my gold medals.
'So right now I am just going out and having a lot of fun and it's working so far.'
Long's world record was one of seven at the Aquatics Centre tonight.
Further marks were set by China's Pan Shiyun in the men's 50m Butterfly - S7 in 29.49, Andre Brasil, of Brazil, in the 50m Freestyle - S10 in 23.16 and Marc Evers, who recorded 1:01.85 in the 100m Backstroke - S14.
Summer Mortimer of Canada lowered her own 50m Freestyle - S10 world record by 0.07 seconds to 28.10, Italy's Cecilia Camellini cut her 100m Freestyle - S11 mark by 1.27 seconds to 1:07.29 and Nataliia Prologaieva recorded 3:13.43 in the 200m Individual Medley - SM5.
Meanwhile, in the men's 100m Backstroke - S9 defending champion Matthew Cowdrey of Australia successfully recovered from a poor performance in the heats to win gold, claiming his ninth Paralympic title in the process.