Sascha Kindred won Britain's first swimming gold in the 200m individual medley SM6 and his fifth in total on a dramatic opening day in Beijing.
The 30-year-old also smashed the world record to secure his third successive title in the event in his fourth Games.
"I'm very proud. It's the pinnacle of any athlete's career," he said.
Jim Anderson won silver in the S2 200m freestyle, as Natalie Jones (SM6 200m individual medley) and Matt Walker (SM7 200m individual medley) claimed bronze.
Following Britain's three golds in the velodrome earlier on Sunday, Kindred did not disappoint with a stunning performance in the pool.
606: DEBATEAfter stunning the packed crowd in the Water Cube with a new world record in two minutes 42.19 seconds, he said: "To go faster than I've ever done here tops it off. I'm ecstatic.
"I watched some of the cycling earlier. Watching it on the TV, a gold medal, it makes the whole team rise to the occasion.
"That was extremely tough. I'm very proud - I knew the Chinese would be tough but I just gritted my teeth and managed to hold them off."
The Hereford swimmer will chase a third successive gold in the 100m breaststroke later in the week, and will also hope for a medal in the 50m butterfly.
Scottish star Anderson grabbed an impressive silver in the S2 200m freestyle, pipped by Russia's Dmitriy Kokarev who beat the Scot's world record to win in 4:45.43.
The 45-year-old, winning his 14th Paralympic medal, said: "I'm happy. My time could have been quicker in the final but I know I have enough left for my next three events."
"I didn't think I would ever win a medal. It was an amazing swim"There was huge disappointment for Britain's Natalie Jones, as she picked up bronze in the SM6 200m individual medley - a race won by American Miranda Uhl.
Jones, hampered halfway through the race after losing her hat, said: "I'm devastated. I feel so sorry for all my fans.
"I'm lost for words and distraught. I race again on Monday but that was my main race."
In contrast, Matt Walker was delighted with his bronze in the SM7 200m individual medley. US swimmer Rudy Garcia Tolson won the gold, smashing his own world record in 2:35.92.
Walker said: "I didn't think I would ever win a medal. It was an amazing swim.
"I'm a lot fitter than I have ever been - I'm just really happy. It's brilliant."
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