Mutual admiration keeps Hamilton, Vettel on track

SAKHIR, Bahrain - Lewis Hamilton goes into this weekend's Bahrain Grand Prix determined to build momentum in his bid for a fourth world title and to keep his battle with Sebastian Vettel as friendly as possible.

After three highly competitive and often acrimonious years competing with now - retired 2016 champion and former Mercedes teammate Nico Rosberg, Hamilton is relishing a different kind of challenge this year.

Instead of fighting his Mercedes partner, newly recruited Valtteri Bottas, he's in a scrap for glory with four-time champion Vettel of Ferrari.