The triple world 200m champion was happy with her outing as she trains towards possibly attempting a 200m-400m double at the August 27-September 4 World Championships in Daegu, South Korea.
Felix held off a spirited comeback from Botswana's Amantle Montsho down the home stretch to coast to the win in a world lead of 50.33sec.
"It's a decent time, nothing special," said the Los Angeles native. "We went out very conservatively in the first 200m because it was windy.
"That made us work hard and Montsho is always strong and she pushed all the way to the end."
Felix, winning in Doha for the 10th time in recent years, added: "It is a very long season so I just want to take things slowly and progress. There's lots more work to do.
"Now I know where I am at and what I have to work towards. I will now focus on my speed and the first part of the race."
There was no such dream start to the outdoor season, however, for Felix's team-mate Lolo Jones, for whom a bout of debilitating sciatica put paid to her indoor season.
Jones, the two-time world indoor champion, had to be happy with third in the 100m hurdles (12.67sec) behind compatriots Kellie Wells (12.58) and Danielle Carruthers (12.64).
Even worse was to come for Frenchman Renaud Lavillenie, who failed to progress beyond 5.50m in the men's pole vault, far off the French record of 6.03m he set when winning European indoor gold in Paris in March.
The event was eventually won by Germany's Malte Mohr (5.81m).
France's Teddy Tamgho dominated the triple jump, winning easily with a best leap of 17.49m ahead of Leevan Sands of the Bahamas and Cuban Alexis Copello.
"I won and that was the essential," the world indoor champion said. "17.40-50 is the minimum I've set myself for the season, the base can only increase from here.
"But with all the training of the last few weeks, I couldn't have aimed for 17.90."
Kenya's 1500m Olympic champion Asbel Kiprop showed his versatility by storming to victory in the 800m in 1:44.74, ahead of Briton Michael Rimmer and compatriot Alfred Yego, the 2007 world champion.
In the absence through injury of world record holder David Rudisha of Kenya and Sudan's two-time world indoor champion Abubaker Kaki, Kiprop was in control from start to finish.
"If Rudisha and Kaki were in the same race, I'm sure I could have run faster," said Kiprop.
Ethiopian Yenew Alamirew became the ninth fastest athlete over 3000m (7:27.26), sprinting home ahead of vaunted Kenyan duo Edwin Soi and Eliud Kipchoge.
With the Kingston International Invitational meet scheduled for Saturday, the leading US and Jamaican sprinters opted to compete there, and organisers here eventually decided late on to scrap the men's 100m.
Walter Dix, who won double Olympic bronze in Beijing, was one American sprinter to make the trip to Doha and he won the 200m comfortably in 20.06sec.
"Walter Dix is reloaded!" he said. "I started the season very strong and that was a great opener. I didn't train in January and missed the indoor season but now I feel very strong.
"I'm aiming high in Daegu and I can tell you that everyone is beatable."
Louis Van Zyl (48.11sec) and Cornel Fredericks notched up a South African one-two in the men's 400m hurdles, pushing American defending world and Olympic bronze medallist Bershawn Jackson into third.
In field events, Estonia's world and Olympic champion Gerd Kanter left it late in the men's discus, managing a best of 67.49m on his final attempt to trump 39-year-old Lithuanian rival Virgilijus Alekna.
It was a repeat in the men's shot, with Canadian Dylan Armstrong (21.38m) also keeping his best until last.
American Funmi Jimoh wrapped up the women's long jump with a world lead of 6.88m, ahead of Brazilian Olympic champion Maurren Maggi.