Vail's finish is the highest by an American in London since 2009.
The American said his run-up to London was the best training for a marathon he's had.
The two runners will take to the streets of London in Mo Farah’s shadow this weekend.
The double Olympic gold medalist finished second despite hitting the pavement hard.
The double Olympic gold medalist will have his hands full against a loaded field of superstars.
The double Olympic champion is prepping for his marathon debut on April 13.
The reigning London and New York City Marathon champion headlines a power-packed lineup.
The annual race through the British capital will be Farah's first time racing the 26.2-mile distance
He debuts in London next year.
The Ethiopian legend may be in London next year.