Goals from Simon Russell and Brian Saah helped Cambridge battle back from 2-0 down to earn a point against big-spending Crawley at the Abbey Stadium.
Matt Tubbs headed the visitors in front before turning in Sergio Torres' cross to double their advantage.
Russell seized on Conal Platt's pass to pull one back before Saah headed in James Jennings's centre to level.
Adam Quinn was denied by home keeper Simon Brown as Crawley sought a winner, while the U's Glenn Wilson headed wide.
Cambridge boss Martin Ling told BBC Radio Cambridge: "We threw two goals away and it looked like we'd never played together in our lives.
"They scored two goals without a challenge going in from our players.
"Give the lads their due, after that they had to show some character and did that but it wasn't the ideal start to our home campaign."
Crawley manager Steve Evans told BBC Sussex: "It could have been a lot more. Anyone who watched the game knows it could have won here 5-2. We gave a couple of bad goals away. [Simon] Brown made three fantastic saves.
"We dominated the play and made good chances. We could have been three or four up before Cambridge got in the game.
"We played some fantastic football in the second football. We carved them open three or four times. And the quality of our play is only going to get better. We are a team to be reckoned with and we will be there."
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