Filus, the world number 35, looked to be cruising having taken a two-game lead over Czech Republic’s Tomas Polansky, ranked 150^th in the International Table Tennis Federation (ITTF) rankings, but his opponent hit back to win the last three games and set up a round of 16 tie with Hungary’s Nandor Ecseki.

Pitchford is ranked 14^th in the world, but twice fell behind to Hungary's Ádám Szudi, ranked 115^th by the ITTF.

However he clinched the last two games to progress to a second round tie with Belarusian Aleksandr Khanin.

In the bottom half of the draw, Aruna also had to show his mettle and win the final two games to avoid an upset against Austrian Andreas Levenko.

The Nigerian will now play France’s Alexandre Robinot tomorrow.

The fifth seed and Filus’ compatriot Benedikt Duda suffered an early exit after being beaten 11-6, 10-12, 5-11, 13-11, 11-3 by Finland’s Benedek Olah.

Home favourite Bence Majoros - the eighth seed and world number 60 - lost to Germany’s Fanbo Meng in straight games, while Slovenia’s ninth seed Lubomir Pistej won the first game but then lost three on the spin as he was eliminated by Italy’s Niagol Stoyanov.

The remaining seeded players, Sathiyan Gnanasekaran of India, Russia’s Kirill Skachkov, Germany’s Dang Qiu and India’s Harmeet Desai all progressed, although Desai had to come from two sets down against Hungary’s Csaba Andras to set up his clash with Qiu in the next round.

In the women’s singles competition, fifth seed Yana Noskova was the highest ranked player to be defeated, losing in five games to Archana Girish Kamath of India.

Seventh seed Dora Madarasz won the first game against Mercedes Nagyvaradi in a clash between two Hungarian players, but her opponent hit back to go through 9-11, 11-6, 11-9, 11-4.

Italy’s Debora Vivarelli, the tournament’s eighth seed, also suffered an upset against Serbia’s Sabina Surjan, the world number 137 triumphing 11-6, 7-11, 13-11, 11-6, and Chile’s Paulina Vega made it four of the top seeds who faced elimination as she lost a five-game match to Italy’s Giorgia Piccolin.

Top seed Xiaoxin Yang of Monaco had no such difficulties, beating Hungary’s Bernadett Balint in straight games, a feat matched in the opposite half of the draw by Russia’s second seed Polina Mikhailova against England’s Tin-Tin Ho.

Yang will face another Hungarian player in Szandra Pergel - the tenth seed - in the round of 16, while Mikhailova will go up against Izabela Lupulesku of Serbia.

The host nation’s Georgina Pota, seeded third in the tournament, eased through with an 11-3, 11-7, 11-3 victory over Tatiana Kukulkova of Slovakia, while the Slovakian fourth seed Barbora Balazova saw off Andrea Todorovic of Serbia.

Sixth seed Manika Batra of India and world number 76 Pergel both had to go the distance to edge past Germany’s Sabine Winter and India’s Reeth Tennison respectively.

The WTT Contender Budapest is a fourth tier event in the WTT structure, and the first ever WTT competition held in Europe.

The round of 16 in the men’s and women’s singles is scheduled to take place tomorrow.