Ousamma Mellouli, Olympic 1,500m free champion, added a further two wins at the Missouri Grand Prix on Sunday, the 30-lap victory his in a solid 15:01.65 that augurs well for the season ahead. 

The distance ace also had it in him to keep sprinters at bay in the 100m free, a 50.15 good enough for victory. Mellouli was one of two Dave Salo charges to emerge as swimmers of the meet, Rebecca Soni the best woman with swift efforts over 100m and 200m breaststroke. 

Mellouli, who had won the 200m free, 400m free and 400m medley earlier in the meet, has never swum faster over 1,500m at this time of the year. A man with eight sub-15min swims on his record, half of those sub 14:50 and two sub 14.40, Mellouli's best early season time is a 14:59.97 from April 2009, while his best pre-summer swim is a 14:55.43 from May 2009 on his way to victory at the world championships in Rome that went down in history as the shiny suits circus at which materials being worn contributed heavily to 43 world records being broken in eight days. Such suits were banned on January 1, 2010. 

Mellouli's latest effort is better than any of his long-course swims of 2010, the best of which was a 15:11.21, as he makes his way towards world titles in Shanghai, where he will face the man who has come closer to any other to retired Grant Hackett (AUS) on the clock - Sun Yang (CHN). In Beijing in 2008, Mellouli denied (by 0.69sec) Hackett what would have been an historic third Olympic victory over 1,500m. 

On Sunday, Mellouli swam a negative split, the first 50m his only sub-30sec one-length split in the first half of the race, compared to seven such efforts and two or three near misses in the second half of the race.

The splits: 

27.71; 57.98 (30.27); 1:28.60 (30.62); 1:59.08 (30.48); 2:29.67 (30.59);  3:00.04 (30.37); 3:30.35 (30.31);  4:00.82 (30.47); 4:31.23 (30.41);  5:01.78 (30.55); 5:32.06 (30.28);  6:02.54 (30.48); 6:32.94 (30.40);  7:03.31 (30.37); 7:33.74 (30.43);  8:03.84 (30.10); 8:33.81 (29.97); 9:03.95 (30.14); 9:34.02 (30.07); 10:04.09 (30.07); 10:33.90 (29.81); 11:03.87 (29.97); 11:34.00 (30.13); 12:04.01 (30.01); 12:34.15 (30.14); 13:04.40 (30.25); 13:34.22 (29.82); 14:04.20 (29.98); 14:33.28 (29.08); 15:01.65 (28.37).

In other action at the US grand prix, Markus Rogan (AUT), another member of Salo's squad putting in  swift early season efforts, won the 200m medley in 1:59.49. His squad teammate Jessica Hardy clocked 54.66 to win the 100m free ahead of Amanda Weir (55.25) and Kara Lynn Joyce (55.48). Soni did not have it all her own way, finishing second in the 200m medley on Sunday to  Whitney 2:17.42 to 2:17.92, third going to Julie Stupp, in 2:18.60.

Chloe Sutton (USA) had another solid meet, adding victory over 800m freestyle, in 8:34.55, to wins over 200m and 400m earlier in the meet. "I’m really training hard, so I’m pleased with my performance. I had a best time in my 200 free the first night, and that was really special for me to be able to do that here. I’m really happy with the way things have been going," said Sutton.

Elsewhere, Nick Thoman (USA) won the 200m back in 1:59.68, comfortably ahead of Tobias Oriwol (CAN), on 2:01.06 and Charlie Houchin, on 2:02.14, while the women's 200m back went to Kylie Stewart in 2:13.88.

Results at a glance (all swimmers with n country attached are USA):

• Men:
• 200 individual medley: 1. Rogan (AUT) 1min 59.49secs, 2. Andrew Ford (CAN) 2:03.34, 3. Robert Margalis 2:03.78
• 200 backstroke: 1. Thoman 1:59.68, 2.  Oriwol (CAN) 2:01.06, 3. Houchin 2:02.14
• 100 freestyle: 1. Mellouli (TUN) 50.15, 2. Richard Berens 50.62, Matt Grevers 50.65
• 1,500 freestyle: 1. Mellouli (TUN) 15:01.65, 2. Arturo Perez Vertti (MEX) 15:48.44, 3. Matias Koski 15:55.06
• Women
• 200 individual medley: 1. Myers 2:17.42, 2. Soni 2:17.92, 3. Stupp 2:18.60
• 200 backstroke: 1. Stewart 2:13.88, 2. Katy Murdoch (CAN) 2:15.06, 3. Annie Harrison (CAN) 2:16.53
• 100 freestyle: 1. Hardy 54.66, 2. Weir 55.25, 3. Kara Lynn Joyce 55.48
• 800 freestyle: 1. Sutton 8:34.55, 2. Gillian Ryan 8:49.18, 3. Amber McDermott 8:52.08