ISTANBUL, Turkey—If you like watching a top-level clay-courter attempt to frustrate an elite hard-courter, than Sara Errani is your woman. The former Roland Garros finalist still spends much of her time camped well behind the baseline on hard courts, but she is willing to take over the net when given the opportunity and on occasion flattens a ball out from the baseline.

But while Errani—who in addition to her clay credentials reached the 2012 U.S. Open semifinals—can give just about every other elite player a tussle on fast surfaces, winning matches is another thing all together.

That was evident in Li Na’s 6-3, 7-6 (5) victory over Errani in the White Group on Wednesday. Errani poked and prodded Li, but in the end, the top Chinese player’s ability to consistently take the ball on the rise, play inside the baseline, and stay aggressive was what won her the contest. Errani’s hope that Li would mentally implode if she put enough balls back in play turned out to be her undoing.

At the start of the match, Li was sometimes firing balls successfully deep into the corners, and at other times was missing her targets by the length of the Great Wall of China. But Errani's serve was punch-less and poorly placed, so even though Li missed a number of second-serve returns early on, she kept taking big cracks at the ball and eventually found her range.

Li broke Errani to 3-2 when the Italian unusually double faulted, and closed the first set out in admirable fashion, nailing an overhead, ace, backhand cross-court winner, and another overhead to win the game at love.

When Li is on, she is essentially an A-minus version of Serena Williams. She does not have as much pop on her first serve, but it is still a very good one. She is a fine mover, owns a ferocious return, has ample power off both wings and is a decent but not sure-handed volleyer. But week-in and week-out the 2011 Roland Garros champion does not compete nearly as well as Serena does. She does not have Serena’s keen focus or seemingly unshakeable confidence and has even described herself as fragile.

That was clear in the second set, when she double faulted to be broken to 3-1. Still, Li broke right back to 3-2 when Errani pushed a backhand into the net. Errani’s heavily topspun forehand can be very effective on clay, but today it was landing with a plop, and Li jumped all over it.

Li broke Errani at love to go up 4-3, easily held, and it appeared that she would ease to victory. But holding her first match point at 5-3, she dumped a forehand into the net and Errani eventually held.

Then Li grew a bit nervous trying to serve the match out. While she fought off her three break points with some huge winners, she found the net with a backhand and was broken to 5-5.

They traded breaks and went into the tiebreaker, where Errani just wasn’t ambitious enough until it was too late.

With Li holding three more match points at 6-3, Errani struck a backhand volley winner off her shoe tips, and then slapped a return and charged, which forced Li into an error. But those two headstrong points were followed by a more routine one, with Errani standing well behind baseline trying to play a routine forehand down the middle. It landed in the net, and the Italian left the court with a miserable 1-32 record against Top 5 players.

With her Tuesday defeat at the hands of Victoria Azarenka, Errani is now 0-2 in her round-robin group and has almost no chance of reach the semifinals. On fast courts, Errani is an entertaining foil against the top players, but she has not proved herself to be any better than that.