Andrey Rublev has added his voice to criticism of the current ATP ranking system with the Russian world No.8 suggesting after winning his opening match in Dubai on Tuesday that it does not work in his favour.

Alexander Zverev, the German world No.7, recently described the revised system as "absurd" because he is ranked lower than Roger Federer even though the Swiss missed an entire year due to knee surgery.

The system was introduced to protect players who are unable to travel and compete because of the coronavirus pandemic.

While players can add points to their tally, they do not drop the points accumulated from the previous season.

"If we would have the normal system, I would be like No.4 in the world I think. So what do you think is better for me, to be No.8 or No.4?" said Rublev when asked if he agreed with Zverev's statements.  

"With the system that we're having now, for me, it's much tougher to be No.4, so here is the answer."

Rublev extended his winning streak at 500-level tournaments to 21 matches after he beat Finnish qualifier Emil Ruusuvuori 6-4, 6-4 in the second round in Dubai.

The Russian, who has won his last four events at this level dating back to Hamburg last September, will next tackle American 15th seed Taylor Fritz or freshly-crowned Doha champion Nikoloz Basilashvili in the last-16 stage.

The second-seeded Rublev faced no break points against the 21-year-old Ruusuvuori and unleashed 26 winners, including six aces.

Canadian world No.12 Denis Shapovalov said he plans to compete in fewer tournaments this season if the tennis tour continues to operate under strict coronavirus bubble conditions for players.

Shapovalov, who enjoyed a winning debut in Dubai thanks to a 6-1, 6-3 second-round success over German big-server Jan-Lennard Struff, says being confined to a hotel room at every tournament due to Covid-19 restrictions can take a mental toll on players.

"I definitely don't want to play too much this year if it's going to be a bubble life because it is extremely difficult mentally to be locked up like this," the 21-year-old said.

"Of course it's amazing to play, but as the weeks go on, you kind of lose that passion for tennis and a lot of players are struggling with that. So we're trying to take the approach of minimising that as much as possible and just enjoying every match that I do go out and play this year."

Over on Court 2, surprise Australian Open semi-finalist Aslan Karatsev, who received a wildcard into the Dubai main draw this week, upset No.12 seed Dan Evans of Great Britain 6-4, 4-6, 6-4. The Russian will take on Italian Lorenzo Sonego in round three.

Italian No.16 seed Jannik Sinner came out on top in a tough battle against Alexander Bublik 2-6, 7-6 (7/2), 6-4 to set up a clash against 2018 Dubai champion Roberto Bautista Agut.

Russian eighth seed Karen Khachanov survived a tight affair with recent Singapore champion Alexei Popyrin to squeeze through in a third-set tiebreak. His reward is a last-16 showdown with French veteran Jeremy Chardy.