(CNN) -

This World Cup is no protector of reputations.

Nor is it anything other than steadfast in its refusal to reveal any clear favorite to hoist the 20th incarnation of football's prime feast.

Argentina certainly counts as one of a pool of nations capable of capturing glory, but its performances so far have shown a worrying brittleness.

Still, it just keeps on winning and can now look forward to a last eight clash with either the United States or Belgium.

The latest side to come close to toppling La Albiceleste was Switzerland, but just like Bosnia and Herzegovina, Iran and Nigeria before them, one moment of magic was all that separated the two in Tuesday's penultimate last-16 clash.

With the contest a matter of seconds away from penalties, the decisive blow was conjured between two men who operate at opposite ends of Spain's fiercest rivalry.

Lionel Messi, of Barcelona, drove deep into Swiss territory and swept the ball wide for Real Madrid's Angel Di Maria, who stroked confidently into the corner.

Yet there was still more agony for Switzerland to endure.

With even its goalkeeper playing as a striker, a point-blank header from Blerim Dzemaili crashed against the post before squirming wide in the 122nd minute.

Argentina's fevered reaction upon the final whistle underscored a palpable sense of relief that its bandwagon continues to edge closer to a first triumph since 1986.

"I was nervous towards the end because we couldn't score and any mistake could have knocked us out," Argentina captain Messi told a press conference.

"The minutes were passing by and we didn't want the match to go to penalties. We were suffering, but we had a special play, I passed to Angel and now we can celebrate."

With Switzerland keen to limit any slice of space for Argentina's array of attacking talent to operate in, the opening stages of the game in Sao Paulo were predictably tight.

There was a glimpse of goal for Messi a little under the quarter hour mark but his stabbed cross-shot was pocketed by Swiss goalkeeper Diego Benaglio.

Once the contest had settled into a pattern, Argentina's failure to engage an powerful offensive arsenal afforded Switzerland a growing confidence which reflected in its play.

The game's first gilt-edged opening arrived on 28 minutes, and it was one carved out by two players who operate in Germany's Bundesliga.

Bayern Munich star Xherdan Shaqiri found midfielder Granit Xhaka, who plays for Borussia Mönchengladbach, with a pullback but his low, powerful drive was repelled by Sergio Romero.

Paris Saint-Germain star Ezequiel Lavezzi tested Benaglio from striker Gonzalo Higuain's knockdown as Argentina looked to reassert its dominance.

Shaqiri was again the provider when a sharp counter attack released Josip Drmic in on goal.

With Romero caught in two minds whether to hunt down the through ball, the Bayer Leverkusen striker looked to take advantage with a chip but got the execution horribly wrong.

Argentina's stopper continued to look uncertain after the interval as he spilled a Shaqiri free kick from range and had to scramble to prevent the ball from escaping his penalty area.

As the hour mark loomed Argentina rediscovered a glimmer of its attacking brio, with Switzerland forced to retreat further and further towards its own goal.

As red-shirted legs became heavy La Albiceleste pressed for the breakthrough and Benaglio was prompted into action when Marcos Rojo's attempted cross crept towards the net.

Higuain then rose highest to power a header towards goal but Benaglio was alert to acrobatically divert the Napoli striker's effort over the bar.

Perhaps inspired by the goal of the tournament so far -- James Rodriguez's explosive volley in Colombia's last-16 win over Uruguay -- Messi attempted his own, firing narrowly over the bar.