Complex sentence: The Red Bull cars had been running in first and second place when the stops began, with Webber emerging from the pits fractions of a second ahead of Vettel and the two immediately began to race each other for the lead.
Split into simpler sentences: The Red Bull cars had been running in first and second place when the stops began. Webber emerged from the pits a fraction of a second ahead of Vettel and the two immediately began to race each other for the lead.