Leicester gave their Premiership campaign much-needed impetus after condemning Gloucester to a third successive home defeat in all competitions.
The Tigers, in an unfamiliar 11th place before kick-off, prevailed through second-half tries from Flood and Samoan wing Alesana Tuilagi.
Flood added three penalties, with his England half-back partner Ben Youngs relieved that a glaring blunder - a reckless pass intercepted by captain Luke Narraway that produced Gloucester's solitary touchdown - did not cost Leicester dear.
Flyhalf Freddie Burns booted three penalties during a tight and tense encounter, but Gloucester again finished second best on home soil following losses to Saracens and Harlequins.
Cockerill added: "It is an exceptionally good result for us to come here and win. It could have gone either way, the tiniest things turn games.
"I thought the way the lads kept their composure under pressure was good and we defended very well again. Leicester sides under pressure generally come up with the goods.
"We are slowly taking shape and we've got to keep working at it."
After losing both their opening Heineken Cup pool fixtures, Gloucester know they must quickly get things back on track, starting with a tricky trip to Newcastle in the Premiership next Friday night.
Saturday's result means Gloucester have lost three in a row at home for the first time in six years.
"I thought we were far better today than against Harlequins last week," said Gloucester head coach Bryan Redpath.
"It wasn't going to be a flash game and I don't think there was that much between the sides, but credit to Leicester.
"We probably should have made a bit more of having the wind with us in the first half and I am disappointed that we have lost at home again.
"Newcastle away is a massive game for us. We can't rely on our home form at the moment, so we have to rely on some of our away results."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.