Luton, winners of the Conference last season, triumphed 1-0 at Carlisle United to taste joy in their first Football League match for five years thanks to striker Mark Cullen's close-range finish on the half-hour mark.
Meanwhile. Cambridge overcame Plymouth Argyle by the same scoreline, Richard Money's men marking the end of their nine-year League exile with triumph through defender Josh Coulson's 61st-minute strike, which came after Adam Cunnington had missed an early penalty.
Morecambe were the most impressive performers of the day, winning 3-0 at Dagenham and Redbridge, while Wycombe Wanderers were 2-0 victors at Newport County.
Title favourites Portsmouth were held to a 1-1 draw at Exeter City in a game that saw home manager Paul Tisdale name himself as a substitute as an illness swept through their squad.
James Collins scored a double in an entertaining 2-2 draw between AFC Wimbledon and Shrewsbury Town, the striker hitting home his second six minutes from time to rescue a point.
Lukas Akins' 42nd minute strike gave last year's beaten play-off finalists Burton Albion a strong start to their promotion push with a 1-0 success at Oxford United.
Tranmere Rovers continued the theme of recently relegated sides failing to win, joining Carlisle and Shrewsbury in doing so as they required a 94th-minute goal from James Rowe to rescue a point against York City.
But there was better fortune for Stevenage - bottom of League One last term - who overcame Hartlepool United 1-0
Elsewhere, Southend United won 1-0 at Accrington Stanley, whose Lancashire neighbours Bury were beaten 1-0 by Cheltenham Town, and Northampton Town defeated Mansfield Town by the same score.