LONDON, Great Britain - In the first of Day 4's two battles of former junior champions, No.17 seed Ashleigh Barty put on a supreme display of grass-court tennis in disposing of qualifier Eugenie Bouchard 6-4, 7-5.

It is the 2011 girls' titlist's second win over Bouchard in as many meetings, having also defeated the Canadian 6-4, 5-7, 6-3 in the first round of Miami last year, and moves her into the third round at SW19 for the first time in her career.

Both players emerged from a cleanly played first set with positive shotmaking ratios, but it was Barty who hit her mark more often and in more ways: the Australian racked up 17 winners to a paltry five unforced errors, excelling both in the forecourt and at the baseline. Her multifaceted game showcased both power on the forehand and deft touch on the backhand slice, which she would successfully use to pull Bouchard into net - where Barty could pick her off with pinpoint passes, two of which paved the way to a break of the Canadian's serve in the third game.

Ashleigh Barty drives a forehand against Eugenie Bouchard at Wimbledon 2018 (Getty)

The bedrock of the 21-year-old's game was her own serve - which, like the rest of her game, is formidable not for its raw pace but its accuracy and variety. Barty racked up nine aces in the opening set, cleverly mixing up slices out wide with flatter deliveries down the tee, and would drop just two points behind her first serve. Only in closing out the set did the Nottingham champion show vulnerability: as her first serve percentage fell and her groundstrokes began to find the net, Barty was forced to save two break back points before finally coming through on her fifth set point as a Bouchard backhand sailed wide.

Unfortunately for Barty, the minor wobble on serve persisted. Her first serve percentage dipped to 48% in the second set, and her troubles on delivery reached a nadir in the fourth game with three double faults: not good enough to hold off an opponent whose form had also been solid. Bouchard pounced, snatching her first break of serve with a dropshot, and took full advantage of the momentum shift.

Eugenie Bouchard dives for a volley against Ashleigh Barty at Wimbledon 2018 (Getty)

The 2012 girls' victor, who has seen her fortunes rebound since hiring Robert Lansdorp as her new coach, also adapted her strategy smartly in a bif to avoid being yanked around on the baseline. Having ventured forwards only four times in the first set - mostly as a result of Barty dragging her to the net - Bouchard took volleying matters into her own hands, storming into the forecourt 12 times in the second act. The tactic was successful: the World No.188 would slam away a number of key overheads as she built up a 5-2 lead to stand on the brink of snapping her 10-set losing streak against Top 20 opposition.

Read more: 'I feel I can help her get better,' say's Bouchard's new coach Robert Lansdorp

But when Bouchard spurned a set point in the eighth game with a cheap forehand mistake, it was suddenly Barty who was revitalized. Chasing down a dropshot to hold, the Sydney finalist peaked on the slice in the next game to break back: a delightful point in which Barty hauled the 2014 runner-up hither and thither before dinking a sliced winner down the line, a clever shot that scythed into Bouchard's feet to elicit the error on break point.

Barty's creativity continued to pay dividends as a brilliant lob was followed by a delightful dropshot return of serve to break again for 6-5 - and though Bouchard valiantly staved off four match points in the final game, a forehand into the net on the fifth would seal the win for the Australian. The result extends Barty's grass record in 2018 to 12-2 - and sets up an intriguing third-round clash against either No.14 seed Daria Kasatkina or Yulia Putintseva.