Gills made to wait, Shots lose
Watford manager Gianfranco Zola insisted his side will battle on despite seeing their hopes of automatic promotion knocked by their 3-2 defeat away to Peterborough.
The home side took a three-goal lead after Danny Swanson, Dwight Gayle and Lee Tomlin all scored.
The Hornets reduced the deficit to 3-2 courtesy of goals from Mark Yeates and Fernando Forestieri but could not find a leveller.
Defeat, combined with Hull's 2-1 victory over Ipswich, leaves Zola's side six points adrift of third place in the Championship.
Zola was also angered by the performance of referee David Webb, who sent off Watford defender Marco Cassetti and ignored strong penalty appeals in both halves.
"It was a bad day for us and getting automatic promotion will now be very tough, but we will keep on fighting as you never know what can happen in football," said the Italian.
"We battled on until the end and could even have got a draw if the game had lasted a little bit longer.
"We paid the price for making some stupid mistakes and also for a couple of decisions that the referee could have made in our favour.
"I thought we should have had two penalties which were not given, and it is not the first time this has happened to us.
"I see things on the pitch that make me believe we have not been treated well and I said that to the referee."
Michael Hector's first Cheltenham goal denied Gillingham the chance to clinch the npower League Two title.
The centre-half, on loan from Reading, headed home Billy Jones' corner as the Robins maintained their own automatic promotion challenge with a 1-0 win.
Second-placed Port Vale were also forced to put the champagne on ice after Rochdale's Jason Kennedy glanced home a stoppage-time equaliser in a 2-2 draw.
Rochdale went in front when Liam Chilvers headed into his own net, but top scorer Tom Pope nodded Vale level moments later.
Chilvers made amends for his earlier error but Kennedy had the last word.
Matt Paterson's injury-time strike earned Burton a 1-0 win against Plymouth and kept them in the automatic promotion places.
Rotherham moved to within a point of the automatic promotion places with a 2-1 win against Fleetwood Town, secured with goals from Daniel Nardiello and Kieran Agard either side of a strike from David Ball.
Northampton were beaten 2-0 by York, who kept their survival hopes alive with a strike from Ashley Chambers and John Johnson's own goal.
Chesterfield snatched a 2-2 draw with Bradford with Sam Togwell's injury-time equaliser.
Bradford twice took the lead, through Nahki Wells and Ricky Ravenhill, but Tendayi Darikwa equalised once and Togwell had the final say.
At the bottom, Aldershot went down 2-1 to Wycombe who took the lead through Matt McClure and Joel Grant got the winner after Craig Stanley's equaliser.
Elsewhere, AFC Wimbledon drew 2-2 with Exeter, Oxford United beat Dagenham and Redbridge 1-0, and Southend drew 0-0 with Bristol Rovers.