Alyson Dixon says she was keen to be the first British female finisher at the London Marathon, as well as securing Olympic qualification.
Dixon and Sonia Samuels secured places for Rio by finishing as the top two British athletes, having already achieved the qualifying time.
"I was like 'I still want to beat you, there's a British Championship at stake'," Dixon told BBC Newcastle.
Dixon was 13th, while Samuels finished eight seconds behind to come 14th.
"It would have been lovely if we had gone 'let's cross the line hand in hand'. But no, you still want the bragging rights," she added.
Both Dixon and Samuels set personal bests at the Berlin Marathon in September to dip under the 2:31:00 qualification standard set by British Athletics ahead of Rio 2016.
Sunderland Stroller Dixon continued: "There was more pressure on myself and Sonia because we were going into the race having already achieved the qualifying time.
"So we knew we had to be the top two Brits to rubber stamp our plane tickets, but it also meant we had a lot more to lose than the others. We could have thrown it away but thankfully we didn't."
Having both grown up in the north east of England, 37-year old Dixon could not be happier to be heading to Rio with Samuels by her side.
"It's absolutely brilliant. If I had to pick one of the athletes that I race against to be on that plane to Rio with us, it would be Sonia," she said.
"We used to race as under-15s and under-17s, so for us to both to get to the stage that we are in life right now, it's just absolutely amazing that we've got there at last."
Samuels, who is now based in Loughborough, says qualifying for Rio is the realisation of a lifelong dream.
"I remember watching the Barcelona Olympic Games (in 1992) and I said to my mum that I was going to do that one day," the Sale Harrier told BBC Sport.
"It was just something that I carried on believing. It's taken 23 years to get there but it was still worth the wait."