(Photo credit: Dan Hamilton-Imagn Images)

No. 5 seed Holger Rune returned from an injury scare a week ago and used a dominant serve to defeat Giovanni Mpetshi Perricard 7-6 (7), 6-3 in the second round of the National Bank Open on Tuesday in Toronto.

The Dane, who withdrew from his opener at the D.C. Open in Washington last week because of back pain, had a first-round bye at the ATP Masters 1000 event in Canada. Rune hit 12 aces with just two double faults against his French opponent Tuesday.

Rune lost just eight of his service points on the day -- converting 33 of 38 on his first serve and 18 of 21 on his second serve.

'I haven't served like this in a while,' Rune said after the match. 'I've been working on some small adjustments on my serve and it seems to be feeling good. It felt really good and I trusted it all the way.

'When (Mpetshi Perricard is) hitting those big serves, there's not much to do, so it's just about focusing on your own serve.'

The seeded players in action early Tuesday encountered little trouble advancing.

Italian No. 3 seed Lorenzo Musetti took down Australian qualifier James Duckworth 7-5, 6-1. No. 8 seed Casper Ruud of Norway beat Russia's Roman Safiullin 6-3, 6-3, and Russian No. 11 seed Karen Khachanov eliminated Argentine qualifier Juan Pablo Ficovich 6-4, 6-2.

Musetti saved both break points he faced and won 90 percent of his first-service points (27 of 30).

The only upset from early action featured Tomas Martin Etcheverry of Argentina defeating No. 24 seed Tallon Griekspoor of the Netherlands 6-4, 7-6 (4).

Only one match from the early slate went three sets. No. 29 Alexandre Muller of France rallied past Serbia's Miomir Kecmanovic 2-6, 6-3, 7-5.

Others who advanced to the Round of 32 included No. 18 seed Alexei Popyrin of Australia, No. 26 seed Alex Michelsen and qualifier Emilio Nava. In a Round of 128 match, Frenchman Corentin Moutet dismissed Jenson Brooksby 6-2, 6-1.

Seven matches still remained, including No. 1 seed Alexander Zverev of Germany taking on Australian Adam Walton. The biggest Canadian name in action will be No. 22 seed Denis Shapovalov, who will face Learner Tien.

--Field Level Media