Dixon won last year's Detroit Grand Prix a race marred by poor track conditions and was followed by Chip Ganassi Racing teammate DarioFranchitti and Pagenaud.
Justin Wilson, who started 24th because he never got a qualifying run in on Saturday, drove all the way to third and pole-sitter DarioFranchitti was fourth in his 250th career start.
Three-time Indianapolis 500 winner DarioFranchitti lost close friend Dan Wheldon at Las Vegas in the 2011 IndyCar season finale, when Wheldon's car catapulted into the fencing and his head struck a support post.
Conway's margin of victory set a race record, beating the 12.2-second cushion 1999 winner DarioFranchitti had over Paul Tracy, and making team owner Dale Coyne seem as if he's the smartest guy in the Motor City.