Robson - who has split with Croatian coach Zeljko Krajan, it was announced - had plenty of opportunities to claim another famous scalp in a matter of days after hammering Radwanska on Monday.
She took the first set and served for the match at 5-3 in the decider, but the 2008 French Open champion came storming back to book her place in the quarter-finals with a 5-7 6-2 7-6 (7/5) win in two hours and 13 minutes.
The encounter contained 83 unforced errors and 15 breaks of serve between them, so it was perhaps unsurprising that Robson served a double fault on match point although no one could argue that it was not gripping.
Robson, 19, secured her first win over a player ranked in the world's top five two days ago although she came stumbling out of the blocks today and while she saved two break points in her opening service game, a double fault handed the advantage to Ivanovic before Robson hit a forehand long.
She immediately broke back, however, and the game went with serve for the next few games.
At 5-5 and 30 all, Robson appeared to be under pressure but showed her growing maturity with two outstanding forehand winners before then setting up a set point in the next game, which she duly converted when Ivanovic meekly sent a backhand into the net.
Robson took her foot off the gas, however, beginning the second set like she did the first as the players traded breaks before Ivanovic opened up a 3-1 lead.
The Serbian then got the double break to go 5-2 ahead and made no mistake by taking the match to a decider.
Perhaps stung into action, Robson immediately broke her 25-year-old opponent and was two points away from opening up a 3-0 lead before Ivanovic pegged her back.
But the left-hander refused to crack under the pressure and a lovely return in the sixth game took her two games ahead once more and she followed that up with a love service game.
Robson could not serve for victory, however, and two breaks of serve remarkably put Ivanovic in pole position to snatch victory from the jaws of defeat.
Once again, Robson showed courage beyond her years to break to love and send the match to a tie-break.
At 4-4, it looked like the game was up for Robson after a forehand winner from Ivanovic and although she got the mini-break back, she could not save the second match point after sending a second serve limply into the net.